I'm not sure
neutral
You do not know the answer.
I'm not sure what time she arrives.
Meaning-first English
How to say "Saying I don't know" in English
I don't know is fine, but I'm not sure often sounds softer and more useful.
I'm not sure
phraseneutral
The safest default: natural, clear, and easy to adapt.
A: Will it be ready today?
B: I'm not sure yet.
Skip: "I want to say saying i don't know" — This describes your search, not what you'd say to a person.
Phrase playground
Pick your exact meaning
Start with the human feeling, then choose the English that fits the moment.
Saying I don't knowWhat do you mean?
I have no idea
neutral
You really do not know.
I have no idea where he went.
I'm not the best person to ask
neutral
Someone else knows better.
I'm not the best person to ask about invoices.
I'll find out
neutral
You will check.
I'm not sure, but I'll find out.
your guess is as good as mine
neutral
You know no more than they do.
Your guess is as good as mine.
Situation check
Choose the moment
Default
You want the simple, natural option.
I'm not sure
Best first choice.
Softer
You want to sound warmer or less blunt.
I have no idea
Good for people.
Stronger
You want more color or emphasis.
I'm not the best person to ask
Use when it fits.
Tone switcher
Say it like...
I'm not sure.
Simple and natural.I'm not sure here, so I'll be careful with the next step.
Work-safe version.I'm sorry, but I'm not sure.
Adds a softener.I'm not sure tbh
Casual only.Native phrase battle
Which sentence best expresses "Saying I don't know" naturally?
With Pro
Go deeper with phrase coaching
Unlock register warnings, richer examples, situation variants, and review decks when Pro opens.
If you learn one, learn I'm not sure.