KD 2.5 : To Express Various Intentions "Expressing Certainty"

·         Being sure.

-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.

-I’m certain…

-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 ….

·         Being unsure.

-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 …

·         Not knowing.

-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.

Example:
Tia : Oh my God, where is my wallet?
Rio : Are you okay?
Tia : I don't know. I think my wallet is lost.
Rio : Are you certain about it?
Tia : Definitely.
Rio : Don't worry. Let me help you to look for your wallet.
Tia : Oh.. Thank you so much, you're really my best friend.
Rio : you're welcome. By the way, where is the last place that you think your wallet already lost?
Tia : hmm, may be in the park.
Rio : Are you certain, your wallet is lost in the street to park?
Tia : I am uncertainty. I think it was lost in the grasses at park.
Rio : Are you sure?
Tia : I am pretty certain.
Tia : okay, let's search my wallet together.



Source: http://administrasigurusmk.wordpress.com/2011/08/01/certainty/#more-128
http://merrysamuel.blogspot.com/2010/09/dialogue-about-certainty-and.html