Certainty :
Yuna : are you sure is not going to rain ?
sulaiman : yes i am sure. i just checked the forecast just now and it says it is not going to rain until the next day

uncertainty :
dina :do you believe it if yuna and sulaiman are cheating on the math test?
yulia : no i don't believe it. they are smart students. they will not cheat on the test especially on the math test. they both like math very much