I'm going to go against the grain here. (Nothing new.)
I feel the best romantic relationships form from very strong friendships.
She may like the idea of your being in love with her and wishes to keep it that way without any obligations on her part.
I know this sounds devious but throw a wrench into the machine.
My sister had the same kind of friendship with her husband. He was in love with her but she felt no chemistry for him.
One night they were at a bar together and he was dancing with a woman and she felt incredibly jealous. That's how they ended up getting together.
The same thing happened with an old friend with a man who was in love with her.

Maybe you could try moving away a little and fix your interest on another woman. I mean, stay friends with her but stop the violins from playing when she's around.

It's the oldest trick in the book. I know- but it worked with 2 couples I know and they are both now married.

If it doesn't work and she calls you on it then more then likely she'll be charmed by it. You lose nothing you don't have now.
Just a sneaky little plan. Hehehe