Difficulty accepting newly discovered half sister

Has anyone else meet an older birth sister who wasn't adopted ? Mine has been a nightmare. very jealous and mean. an emotional manipulator. I am so lost at how to deal with this. it has been 10 years since contact and been trying to figure her out since ( pretty sure she is seriously mentally ill and an alcoholic too ) i keep hoping things will change but dont think this person is mentally healthy enuff for any kind of relationship. i can understand someone not liking you or maybe not wanting to continue a relationship. but to deliberately try to hurt someone and tear them down is mind boggling to me. I do have other siblings i have formed a healthy bond with. I also found a half brother who is same mother as the sister who had made some pretty inappropriate sexual comments to me the first few years in reunion. i dont know what do too im so confused and was NOT prepared for the mess i found. but i keep hope things will change ??? sorry for the rant