Here, at Ain't It Cool News He's a bit more talkative than he's been on previous junkets. Here's my favorite bit (bold mine).
Quint: I think it’s kinda fascinating what they do with your character in the next one. I mean, I’m sure all the focus right now is on the Lavender Brown relationship…
[Grint laughs]
Quint: … And that is good stuff and I’m sure you’re going to have a lot of fun, but the interesting stuff to me is how your relationship with Hermione develops. That kind of true budding romance versus the more lustful thing with Lavender. I think I like it so much because it’s really kind of been set up for a while now…
Rupert Grint: Yeah, gradually. And in this one you see him being a bit more protective as well when she gets picked up by Grawp. He wants to sort of be the hero. But, yeah. In these films there’s always been a sort of hint of that and maybe that’ll kind of feature in the 7th book as well. We’ll see.
He also has lovely things to say about Evanna as well. Quint is supposed to post his interview with David Yates (part of which includes his approach to HBP) later today.
ETA:
Here's his interview with David Yates. *tries not to be smug*