-I’m sure / certain (that) (he will come / …)
-There is no doubt about it.
-No doubt (you’d like to see your gift / …)
-I certainly think / believe that (she was unhappy / …)
-I’m positive on that point.
-It is obvious that …
-That goes without saying.
-It’s crystal clear.
-It’s as sure as two and two make four.
Being less sure.
-I think so
-I think that ( they will be there by 6 / …)
-I suppose so.
-I suppose / expect that ( it is the way to the bus stop /…)
-I believe that ( he is sick / …)
-I assume (that ) (they did it / …)
-It’s more than probable that …
-I wouldn’t be surprised if ….
-I’m not sure (that) …
-I wonder if…
-I doubt if …
-May be / perhaps (they’re right / …)
-It’s very doubtful whether (he’ll accept / …)
-There’s a little chance of (arriving in time / …)
-It isn’t known for use …
-I don’t think so.
-I don’t think that (they will give her a ring / …)
-I don’t know / I’ve no idea / I wouldn’t like to say (where it is).
-I haven’t the faintest idea.
-Sorry, I can’t tell you.