Young love is a flame very pretty often very hot and fierce but still only light and flickering. The love of the older and disciplined heart is as coals deep-burning unquenchable.
Sexiness particularly in movies is the chess game in the 'Thomas Crown Affair'. It's it's I don't know but Faye Dunaway comes up a lot in that thinking. It's the subtlety of sexiness. The moment you try to be sexy then it's not.