It's hard for someone as sheltered and as serious as Garnet to deal with someone so straight-forward and almost pushy as Zidane. At least that's how I saw it.

Zidane was quite clearly attracted to Garnet... but I think Garnet was smart enough to know that, at the beginning, that could be no more that physical attraction. Eventually he gets to know her and genuinely likes her... and I think that's what she starts to respond. I think if she'd given into him easily (like I assume most girls did), he'd have lost interested. But then again, I could just be relating that to guys I know.

If anything, I'd say Zidane acted like Rinoa, but he doesnt... much.