Not corny bro, Oda simply depicted a case of Stockholm Syndrome.
Doflamingo used her for occasional sex, fucking the former King's daughrer was probably a twisted way to assert his control and dominance the real "King" of Dressrosa.
Viola played the game both cause she was probably blackmailed to not resist and because she actually had feelings for Doflamingo, something she sure wasn't proud about.
As he said, Dressrosa is the land of "passion" and Stockholm Syndrome is a form of it, even tho you might find it strange.