Well, I still push. You have enough chips to make him sweat, and from the sounds of it, he's playing his usual style, which is aggro. The bet here, however, is just so funky. First he bets 700, then he calls your pot size raise, then he just lashes out another pot sized bet when a third heart comes up? Well, judging from your actions thus far, he doesn't think you have two hearts. You have a very, very inconspicuous hand. Chances are he puts you on top pair, with maybe one heart. Sounds like he himself has a strong pair and he's defending against a fourth heart OR is now on a flush draw with a pair. Whatever the case, I see him playing a made flush differently. Like I said, I'd push on the turn.