certainly

adverb3

1. •
   Without doubt, surely.

   • The accident was certainly caused by human error.
   • That was certainly sweet of him.
2. •
   An emphatic affirmative answer; of course.

   • Would you like it with ice?
   • Certainly, and with lemon please.
3. •
   for sure, in a way that leaves no doubt

   • The torque was "built up" in the special back axle and the car crawled tankwise but very certainly over the obstacles without a jar or hesitation. — 1923