I couldn't agree with Bob, more. My limited understanding is that there are two basic approaches to love spells: 1) manipulative, which seek to bend the other's will to the spell caster's; 2) attractive, which seek to bring out the attractive qualities and behaviors in the spell caster, so that the intended will notice and respond in the optimal way (whatever that is).
I think #2 would be more likely to lead to a happy outcome. That way, even if the intended lover didn't respond as you want, you, yourself, will have embraced some really great qualities in yourself and begun to express them more creatively...which will make you happier and also might attract whomever really is the right one for you.
That being said, here's a more practical comment. When I was young (I'm a woman, btw), I went for guys I thought were sexy. I had a lot of really great male friends who were interested in me that way, but I wanted to keep my real friends as friends, and not ruin it by bringing all of the stuff that comes with sex into it: lust, possessiveness, power struggles, psychodynamics, etc. Not that the friends weren't great looking, too....but I was into a certain kind of indifference, I guess you could say, which was just bad parenting I hadn't grown out of yet. This is all in retrospect: at the time, I thought these "indifferent" sorts were capable of real love with me, etc....so wrong....youth, as they say, is wasted on the young....:-)
Now, having been in and out of lots of passionate relationships, I kick myself, thinking of how much more likely it would have been to end up happily married (or whatever) with one of those nice guys. I'd love to be able to get up in the morning and just be happy to see someone I want to have coffee with.
My advice would be to really think: are you a good match for this person? Could you honor your friendship by being a faithful friend and mate? If you were both older and had gotten sickly or a bit wrinkly or pudgy, could you trust her to be happy to just be with you and visa versa? If so, you can begin to patiently work towards letting her know that. If she catches on, you'll both have a chance at something potentially very cool.