Wow, something I can kinda-sorta help with! I went through something similar recently, and with help from Dopers made it all work out.
Here’s the whole story of my friend/girlfriend/dating situation.
With her and I, we never had an official date. We’d make out when we got drunk, and kind of cuddle up and hug a lot, even while sober. There was definite attraction, but neither of us were making a move.
Like you, I was unsure how to proceed. It sounds like you’re not 100% into her anyway. I mean, you should be at least a little disappointed when she goes on dates with someone other than you if you’re actually intending to start a relationship with her, right? You say you’d be happy either way, girlfriend or not, but you should be happier if she were to be your girlfriend. If you’re not that interested, then you’re fine where you’re at.
If you do want more, then you’re going to have to act. And it’s hard, I know. There’s all sorts of weirdness since she’s been your friend longer than she has a romantic interest. And don’t even get me started on mutual friends and their responses and yadda yadda. It’s uncomfortable to say the least.
What worked for me was getting way drunk and making out with someone else and letting her find out. She got jealous enough to talk to me about it, also while drunk, and I asked her on a date. For some reason, she accepted.
This isn’t smooth or appropriate in any way. Even though it worked for me, I wouldn’t recommend it.
You say you’re already going on dates. Take her on one, and straight-out ask her. She’ll probably be glad to talk about it, even if its just to tell you she’s not interested. Getting a beer or 2 in you will probably make it easier, but don’t get drunk like I did.
Honestly though, if she’s dating other guys, she’s probably not that interested. The girl I’m currently seeing (yeah, the former friend in that previous post) “held out” for me for almost a year. She didn’t date other guys, but instead spent all her free time with me or her girlfriends. She called all the time when we weren’t together and went out of her way to see me as frequently as she could. I still missed those signals, but that’s not the point. I would imagine any friend-trying-to-be-more would do about the same. Women-folk can chime in and tell me if I’m wrong.
I wouldn’t recommend just trying to kiss her. I got that advice a lot too. Seems like a bad idea if she’s not interested.
And good luck. It worked out great for me, and is easily the best relationship ever. She was already my best friend and I would have done anything for her. Now its more of the same, but… um… better.