A2
used to emphasize something and show that there is no doubt about it
Dictionary examples:
The dog certainly enjoyed eating my homework! (0.0)
The teacher certainly wasn't happy about the flying paper airplanes! (0.0)
I certainly won't eat broccoli ice cream for breakfast! (0.0)
I'll certainly be there. (7.5)
They certainly deserved to win. (16.5)
She certainly knew him but I don't know how close they were. (17.2)
"Do you think more money should be given to education?" "Certainly!" (20.5)