My best friend is one big back-stabber

I've known this girl called lelia for three years and she's really popular, pretty and everybody thinks she's really nice but then I think she isn't. She's been treating me horribly when no one sees. It's so annoying. Really unfair one time cause I was...

just playing around with one of my other best mates I accidentally got her into trouble. I don't know know why, lelia suddenly turned against me and started stealing my stuff with my mate. I didn't mean to get my friend into trouble, the teacher just caught us fighting around. I think whenever I hurt my mate in some way but it's a joke, lelia always teases me or threatens me in some way and I don't know wht to do. I can't tell anyone cause they won't believe me and they'll end up going on lelia's side. What's the point? My best friend is one big backstabber and I know that but nobody else sees it. The point is, whenever I joke around with my mate, my so-called bessie, lelia will always either threaten me or does something that will hurt me.
I don't know wht to do, please please help.

UMM if I were you I would tell her to knock it off and if she doesn't then I would ignore it and apoliggise to her even if its not your fault be the bigger person

I think you
should talk to her.
tell her how you feel.
I mean dude.
its not always the bad thing to talk
to her.
if she continues to act like that.
just
FORGIVEFORGET!

XD