Certainly, actually (6)
I believe the answer is:
indeed
I believe this is a double definition.
'certainly' is the first definition.
(both can be used to answer in the affirmative)
'actually' is the second definition.
(I've seen this before)
(Other definitions for indeed that I've seen before include "Yes, truthfully" , "beyond doubt" , "''A friend in need is a friend . . . . . .''" , "Expression of interest, incredulity or contempt" , "still" .)