he verily thought he had young live frogs in his belly, qui vivebant ex alimento suo, that lived by his nourishment, and was so certainly persuaded of it, that for many years following he could not be rectified in his conceit.
Without doubt, surely.
The accident was certainly caused by human error.
That was certainly sweet of him.
'I'm all grown up now' -'You certainly have (grown)!'
An emphatic affirmative answer; of course.
Would you like it with ice? Certainly, and with lemon please.