How to tell her I don’t like her?

Long story short, I have been in a toxic friend relationship for my whole life. I really don’t like her she is a terrible person to me. I am trying to be a better person and she is holding me back. I am always compared to her. I have tried to get out of this relationship but my birth giver will never let me. What should I do, what should I say to her and my birth giver?