Double confirm 

This is the Singlish way of saying "Yes, I am very sure".
It is usually prefaced by the Singlish way of asking "Are you sure?", which is simply, "Confirm?"

Singaporeans usually either just say "Double confirm" or "Double confirm, chop stamp, guarantee". A chop is a stamp, as in an immigration stamp on your passport. So basically after you've said you are very sure by confirming twice, you stamp it (twice) and guarantee it so the other person knows you are VERY VERY sure.

S1: "Wah, this is the best chicken rice stall in Singapore by far..."
S2: "Really? Confirm?"
S1: "Double confirm, chop, stamp guarantee!"

Double confirm by Dizzydee May 5, 2014