In love with straight girl best friend

I've known one of my best friends for just over three years, but I didn't really get to know her until September 2011. Since then, I've developed this crush on her that won't go away and it's been over a year. She's so kind and beautiful. All I want to do is kiss her and be with her, but I don't know how to tell her I love her. Every time I do, I don't try to press it, or the fact that I might be into girls. In texts, I simply say "I love you" instead of the "<3 u" she gives me. She jokingly flirts with me and kisses me on the cheek, but I think she's only doing it as a friend. I don't want to ruin our friendship, but it's tearing me apart not to be able to tell her. I have no idea what to do.

Find out if she's interested in girls before you risk the friendship by telling her.

I know it can be hard to stop yourself from falling for someone... but falling for straight girls usually ends in DISASTER. Avoid it at all costs.

You could also try taking a little space from her, keeping yourself busy doing something else, or focusing your attention on someone you know to be bi/les.