EXPRESSING CERTAINTY

Theory

To express the faith that something has been/ is being/ will happen, use the following phrases :

-I'm sure : Saya yakin

-I absolutely sure : Saya benar-benar yakin

-I'm certain : Saya yakin

Example

If you have question :

"Will Amir pass the exam?" = "Apakah Amir akan lulus ujian?"

Can respond with :

-"Yes, I'm sure he will" = "Ya, saya yakin dia akan lulus"

Source :
http://spensaguti.wordpress.com/2013/09/12/expressing-certainty-and-uncertaintydoubt/
http://nadiirrss.blogspot.com/2014/01/expressing-certainty.html