A Woman Is Giving Me Mixed Signs… How Do I Approach This?

I’ve met a lady in university class. She’s gorgeous, bright, thoughtful, and matches my wit… everything I could desire. She’s also single.
In just four weeks of knowing her, I’ve met her and hung out with her maybe even more than I do so with my best buddies, mostly at her suggestion.
We bust each others balls all the time. We’re comfortable with each other physically: touching, hugging, wrestling, tickling (mostly her being the one to initiate). Additionally, when we talk sitting together closely, she often looks from my eyes to my lips and back, especially when she came by my place (again, at her suggestion). Normally, that’s pretty much a dead give-away, and I’d go for the kiss.
A few things are holding me back: she constantly says that we should hang out to become friends, or become better friends, the emphasis being on the word “friends”. Also, she says that she’s the “no sex before marriage” type. I don’t have a problem waiting… except that I have decided never to marry on principle. She knows this, so why the hell does she keep giving me signs that she’s attracted?
I’ve given her several hints that she’s confusing me about what she wants but she doesn’t get them, or is pretending not to.
Despite being quite good at telling whether a woman likes me, her innocent nature puts a veil on her intentions and I’m utterly baffled. She could be the type to want to really know who a person is before she dates me, but for me, it’s become more of a frustration.
So, now that I’ve bored you to tears, does anybody have any serious suggestions about how to coax her intentions out of her? I could ask her directly eventually, but it’s preferable not to.