"Quite so" (4)
(Other definitions for true that I've seen before include "Real or correct" , "In accordance with fact" , "Unwavering" , "Real, actual" , "Agreeing with fact or reality" .)
'quite so' is the definition.
(both can be used to express agreement)
This is all the clue.
(Other definitions for indeed that I've seen before include "Actually -- denied (anag)" , "Absolutely" , "Without question" , "Really, without doubt" , "Really - truly" .)