In English, language expressions often feel quirky, full of history and nuance, like puzzle pieces with meaning. Is It Correct to Say “Rest Assured”? Using this phrase is correct, grammatically sound, and widely used to give certainty. It means you can be sure, with no doubt about something.
I once told a friend worried about an upcoming exam, “you’ve studied hard, you’ll do great.” That polite, reassuring way felt like a better choice, helping them feel confident, build confidence and comfort, and letting them know everything was okay.
From grammar and syntax views, rest functions as a soft imperative, a directive in commands or statements, without sounding like a demand. Its form, structure, tone, and formality remain consistent across contexts like meetings, projects, and real-life examples.
I’ve written, “Jonathan will complete the event on time, rest assured,” and heard it even during a police investigation, where officers say, “we’re doing everything we can.” This assurance is a valid, good option for phrasing, with alternatives explained in an in-depth guide that unpacks origins.
Why People Question “Rest Assured” in the First Place
People trip over “rest assured” because it doesn’t follow typical English logic. It sounds formal and a bit old fashioned. That makes learners—and native speakers—wonder:
- Does it mean “rest” like sleep?
- Do you need a verb like be before it?
- Is it actually grammatical?
Most online grammar advice is confusing or contradictory. Some say it’s correct. Others say it’s wrong. The truth lies in usage, history, and structure.
You’ll learn all of that here in clear, actionable terms.
What “Rest Assured” Really Means (Plain English Explanation)
Let’s cut to the chase. “Rest assured” is an idiomatic expression. That means its meaning isn’t literal. You’re not telling someone to rest their body or relax physically. Instead, the phrase signals certainty and reassurance.
Meaning in simple words:
Rest assured = Be confident or be sure about something.
You use it to comfort someone or emphasize that something will happen or is true.
Examples
- Rest assured your message will reach the team.
- You can rest assured we’ll handle this issue.
Notice how it sets the reader or listener at ease? That’s the purpose.
The Historical Roots of “Rest Assured”
To understand why “rest assured” feels unusual, it helps to peek into history.
English used to allow more flexible sentence structures centuries ago. Phrases like “rest assured” appeared in formal writing to mean something like “you may confidently believe this.”
Over time, English shifted toward simpler constructions. But some idiomatic expressions stuck around—especially in formal or written English.
Early Usage
- Found in older legal documents
- Used in polite correspondence
- Appears in 17th–18th century English literature
This history shows:
- The phrase isn’t random
- It’s not broken English
- It is idiomatic and well established
Is “Rest Assured” Grammatically Correct?
The short answer: Yes. It is correct.
But let’s unpack that in a way that actually makes sense.
How Grammar Works With Idioms
Most grammar rules assume sentences follow patterns like subject + verb + object. Idioms break those patterns because they rely on shared meaning, not literal word order.
| Phrase | Literal? | Idiomatic? | Correct? |
| Rest assured | No | Yes | |
| Be rest assured | No | No | |
| You can rest assured | Partly | Yes |
So when we see “rest assured”, the phrase functions as a fixed chunk of meaning—not a literal instruction.
Why It Works
English allows fixed expressions that don’t follow strict grammatical rules when the meaning is well understood by speakers. Think:
- “Let alone”
- “Much less”
- “By and large”
These are perfectly acceptable even though they don’t follow standard patterns.
Why “Be Rest Assured” Is Incorrect
Here’s where many people trip up.
You might see “Be rest assured” and think it sounds formal or polite. But adding “be” actually breaks the idiomatic structure.
Common Mistake
- Be rest assured we will reply soon.
Instead, use:
- Rest assured we will reply soon.
Why?
Because “rest assured” already expresses a complete idea of reassurance. Adding “be” turns it into a weird mash-up that native speakers don’t use.
Side-by-Side Comparison
| Version | Correct? | Reason |
| Rest assured X | Yes | Established idiom |
| You can rest assured X | Yes | Helps soften tone |
| Be rest assured X | No | Extra verb ruins idiom |
| Be assured | Yes | Different structure with clear grammar |
In short:
Stick with “rest assured” or “you can rest assured.” Avoid “be rest assured.”
That’s the rule most professional editors follow.
Auxiliary Verbs and Why They Don’t Belong Here
Now let’s talk verb confusion.
Auxiliary verbs like do, be, have, will help form other tenses or ask questions:
- Do you agree?
- She has gone home.
- Is it ready?
But in “rest assured,” there’s no tense being formed. It’s not a question or a command in the usual sense. It’s a fixed phrase that functions as reassurance.
Adding an auxiliary verb (like be) doesn’t help. It only makes the phrase sound unnatural.
Mental Trick
Think of “rest assured” as a tag that means:
“You can trust this information.”
Rather than:
“Perform some action with ‘rest’.”
Once you think of it that way, the misuse of auxiliary verbs becomes clearer.
How to Use “Rest Assured” Correctly in Modern English
Here’s your practical guide to using this phrase the right way.
Correct Structures
Rest assured that…
You can rest assured…
Please rest assured…
Rest assured, we’re on it.
Contexts Where It Fits
- Professional emails
- Customer service responses
- Speeches and reassurance statements
- Formal writing where confidence matters
Contexts to Avoid
- Very casual chats (it may sound stiff)
- Text messages where brevity matters
- Informal spoken English with friends
Real-World Examples That Sound Natural
Let’s see how this works in practice.
Workplace Communication
- Rest assured the team will finish the project on time.
- You can rest assured we’ll update you by end of day.
Customer Support
- Rest assured your issue will be resolved promptly.
- You can rest assured we take your feedback seriously.
Professional Presentations
- Rest assured this strategy is backed by data.
- Please rest assured we’ve tested every scenario.
Everyday Reassurance
People sometimes use it in regular speech, too:
- Rest assured, I’ll call you when I arrive.
Each of these feels natural because the phrase expresses confidence without excess.
Expressions Similar to “Rest Assured” (With Usage Notes)
If you want variety, here are alternatives. Some are more formal, some more conversational.
Similar Phrases and When to Use Them
| Expression | Tone | Best Use Case |
| You can be sure | Neutral | Everyday reassurance |
| Count on it | Casual | Friendly promise |
| Without a doubt | Strong | Emphasis in speeches |
| You have my word | Personal | Trust-based assurance |
| Rest easy | Relaxed | Comfort-focused reassurance |
Usage Notes
- “Count on it” feels friendly and direct.
- “You have my word” is great in personal commitments.
- “You can be sure” works in both informal and formal settings.
These alternatives help you steer tone depending on audience and context.
Common Mistakes to Avoid With Reassurance Phrases
Even confident speakers slip up. Here’s how to avoid common pitfalls.
Mistake #1: Using overly generic reassurance
Instead of:
No worries, we’ll handle it.
Use:
Rest assured, we’ll handle it promptly.
The second sounds more confident and reliable.
Mistake #2: Mixing idioms incorrectly
Incorrect:
Rest assured, you can count it on.
Correct:
Rest assured, you can count on it.
Small mistakes like missing prepositions change meaning or clarity.
Mistake #3: Using too much formal language in casual text
In a quick text to a friend:
- Rest assured I’ll pick you up may feel stiff
Better:
- Don’t worry, I’ll pick you up.
Tailor tone to context.
Read More: Cord vs. Chord: The Difference Explained Clearly
Quick Reference Guide (Table Format)
Here’s a simple cheat sheet you can refer to when writing.
| Phrase | Correct? | Notes |
| Rest assured | Yes | Core idiom |
| You can rest assured | Yes | Adds gentle tone |
| Be rest assured | No | Redundant verb |
| Rest easy | Yes | More relaxed |
| You can be sure | Yes | Solid alternative |
| Count on it | Yes | Casual variant |
Case Study: “Rest Assured” in Professional Emails
Let’s look at two versions of email responses in customer support.
Version A (Weak)
Hello John,
We received your message. We will update you soon. Thanks.
This feels generic and doesn’t build trust.
Version B (Effective)
Hello John,
Rest assured we received your message, and our team is reviewing it. You’ll get an update by 3 PM today.
Thank you for reaching out.
Notice how “rest assured” gives confidence and clarity.
Impact:
- Sounds professional
- Builds trust
- Sets expectations
That’s how language drives perception.
Quotes From Writing Experts
*Idioms like “rest assured” thrive not because they follow textbook grammar but because they communicate meaning clearly and efficiently.”
— Dr. Helena Morris, Linguistics Professor
Native English speakers recognize comfort phrases instantly. Misusing them can undermine credibility.
— Mark Feldman, Professional Editor
These expert views align with real usage patterns.
Confidence Comes From Correct Usage
By now you should be able to:
- Use “rest assured” correctly every time
- Avoid the common error “be rest assured”
- Choose alternatives when tone matters
- Write reassurances that feel natural and trustworthy
Remember:
“Rest assured” isn’t about resting. It’s about expressing confidence clearly.
Use it well and your writing will feel more polished, more professional, and more reassuring to your readers.
FAQs
1. Is it grammatically correct to say “rest assured”?
Yes, it’s grammatically correct and widely accepted in English. You use it to give certainty and remove doubt.
2. What does “rest assured” actually mean?
It means you can be sure something will happen or is true. It offers comfort and reassurance.
3. Is “be rest assured” correct English?
No, “be rest assured” is incorrect. The correct form is simply “rest assured.”
4. Can “rest assured” be used in formal writing?
Yes, it works well in formal emails, speeches, and professional communication, as well as casual conversation.
5. Why do learners often hesitate to use “rest assured”?
Many learners stumble because the phrase sounds idiomatic and hides grammar rules, even though its structure is simple.
Conclusion
“Rest assured” is a correct and reliable English expression that gives confidence and clarity. When you use it properly, it sounds polite, natural, and reassuring. Whether you’re writing an email, speaking formally, or comforting someone, this phrase helps you communicate certainty without sounding forceful.
