Meaning of "certainly" in Essential American English Dictionary

certainly

adverb us /ˈsɜr·tən·li/

A2 definitely:

They certainly deserved to win.
“Do you regret what you said?” “Certainly not!”

A2 used to politely agree to do something:

“Could you pass the salt, please?” “Certainly.”

(Definition of “certainly” from the Webster's Essential Mini Dictionary © Cambridge University Press)