Dialog ungkapan kepastian dan ketidakpastian

Kepastian : 
A: Hy, can i ask you something?
B: Oh Sure, what's that?
A: Are you sure he will come to my party tonight?
B : Yes, I'm Absolutely he will come.

Ketidakpastian :
C: thank's for accepted me as your facebook's friend
D : Hahaha, Okay.
C: by the way, do you remember our last moment in 12 years ago?
D: No, definitely not.