Depends on the villain and his perception of you. But his range is very polarized here: he's potting as a bluff or if he has the nuts AND puts you on a second best hand. It makes no sense for him to be potting a set there unless there is a whole lot of metagame going on.
Even if he has decided his second straight is good then I don't think he pots it, but either makes a milking bet or tries to induce a bluff. Anyway, I think he has busted hearts here often enough, unless he is a really donkish player who just mashes the pot button whenever he has the nuts.