Definition
Certainly; without a doubt; definitely.
确定，无疑
She said she would come, so she will be here for sure.
她说她会来，所以她肯定会到这里。
I know for sure that I left my keys here.
我确定我把钥匙留在这里了。
They are going to win the game for sure, they are too strong.
他们肯定会赢得比赛，他们太强了。