You can't decide, or you doubt what someone's saying. You want to be honest about it without sounding negative or shutting the conversation down.
Way 1 · best default
Honest and calm. You think you might know, but you can't promise.
Examples
I'm not sure, but I think it's open on Sundays.
I'm not sure that's the right way. Shall we check?
In a conversation
A: Is the market on today?
B: I'm not sure. It was last Saturday, though.
Way 2 · can't decide
You're stuck between two choices and haven't picked a side yet.
Examples
I'm on the fence about the new job. The money's better, but it's far.
Still on the fence about Thai or pizza, to be honest.
Common mistake
Not: I'm standing on the fence.
Say: I'm on the fence.
It's a fixed phrase. Just "on the fence", no "standing" or "sitting".
Way 3 · need time
You're open, but you won't decide right now.
Examples
It sounds great, but I'll have to think about it.
Thanks for the offer. I'll have to think about it over the weekend.
In a conversation
A: So, shall I sign you up for the two-year contract?
B: I'll have to think about it. Can I take a leaflet?
Way 4 · show me more
You've heard the argument, but it hasn't persuaded you yet.
Examples
I'm not convinced the new system will save us time.
It looks nice, but I'm not convinced it's worth the money.
Common mistake
Not: I don't believe you.
Say: I'm not convinced.
"I don't believe you" sounds like you're calling them a liar. "Not convinced" doubts the idea, not the person.
Way 5 · changing my mind
You already decided, but now you're starting to doubt it.
Examples
I booked the flights, but now I'm having second thoughts.
Are you having second thoughts about moving?
Common mistake
Not: I have second thought.
Say: I'm having second thoughts.
Always plural "thoughts", and usually with "I'm having".
Way 6 · quiet doubt
You really don't think it will happen or work, but you say it gently.
Examples
He says he'll be on time. I have my doubts.
I have my doubts about the weather holding up for the barbecue.
Read the moment, then choose the way that fits it best.
Pick one and practise it in a real conversation. Save the ones you want to remember.
