a friend that you are particularly close with and trust, typically, one is more attractive than the other. legally, there can never be two pretty best friends at once, it’s widely considered impossible by many.
Something unfortunately I do not have someone you can confide in tell EVERYTHING to and your friendship does not change. Someone you love no matter what and honestly they trust you a lot. I may not have a best friend but if I did they would have these characteristics. I least I hope so. If you have one remember be thankful and show them how much they mean to you.