I thought Rinoa was kind of a childish, rich bitch so I don't know why somebody would fall for someone like that. I mean if Rinoa was real she'd be kind of pretty I suppose but I wouldn't call her hot or sexy.
If I were Squall I think I would kind of gravitate over to Selphie because in my opinion she wears a mask just he does. Only Selphie's mask is a mask of hyperactivity and cheerfulness while Squall's is a mask of aloofness and antisocial behavior.
I think Rinoa is so transparent. She tells you exactly what she's feeling so she doesn't wear a mask to hide her emotions like Selphie and Squall do. And that means Rinoa isn't a mysterious character she's an open book who can be easily read.