Why are females so fake and backstabbing even though u put your all into the friendship?

I"m so irritated with fake backstabbing females. What is a "friend" ? you can put your ALL into a friendship...but in the end your friend can stab you RIGHT IN THE BACK...and use your name in conversations with your enemies..and come to you and talk about the people they allow to talk about you without speaking up at ALL. If that person does it to their friends they hang with, they'd do the same to me vice versa..