I'm in love, he's not, and there is someone else!?

I'm in my late 20's and life is getting complicated! I have been best friends with a guy for about 4 years, and I have fallen in love with him. I've told him this twice, and both times he said he had no romantic feelings for me. Now I've met this other guy who keeps calling me, and wants to date me, but I won't return his phone calls, because I'm still in love with my best friend. I feel like I would rather hang with him and wish he would someday change his mind, rather than try dating this new guy. Then again, I feel like I need to give this other guy a chance. I'm so confused! I'm afraid if I start dating this new guy my friend will think he can never ever get close to me, and if I don't, I'm sure this new guy will give up on me quickly. What do I do??