Don't ask her. That is SO annoying. If she's looking up at you, into your eyes, making eye contact with "those eyes" and leaning in toward you, she wants you to kiss her.
As I was dropping a girl off, she looked at me and leaned in; somehow I missed it. It ended up being an awkward hug instead. And needless to say, I've never heard from her since.
the exact opposite thing happened to me once... the guy was dropping me off, and I was going to lean over to hug, and I guess he thought I was leaning in to kiss, hahahaha weird hug indeed!