FRIENDS?!

I'm the only girl on my moms side I have two older brothers & the youngest girl on my dads side with 2 sisters and 2 brothers. I've never really been able to keep friends the always turn on me or do something fake towards me and the people that clam to be my best fiend always stab me in the back . Me and my mom are aren't really that close and I'm mainly close with my dad and my boyfriend and I tell me dad everything to a certain extent and my I tell my boyfriend everything but they are men and the can't see it from a girls perspective no matter how hard they try to understand they can't . I have a friend I can talk to but she already has a best friend more like a sister . I literally do everything alone go shopping to the nail salon literally everything unless I take I my niece with me and she's o my 2 I consider her my best friend . It doesn't bother me but than again it does I've only been around boys my whole life and me and cousin were close but she passed away . I just really want a true girl best friend that I can't trust and confined in about anything and go places with. How do I go about finding the right person as a friend ? How do I know that she won't turn on me ?