The Benefit of the Doubt

Me and one of my best friends just had a very heated debate. Neither of us really won or lost because both of us are very stubborn. The debate was over the benefit of the doubt. What does that actually mean and if it's a good thing. The worst part of this debate is that I think I broke the rules because I sort of believe both sides. She says that giving someone the benefit of the doubt is a bad thing because people should have to earn there friendships. I agreed with her on this point but I said that the benefit of the doubt is not automatically letting someone be your friends, it's just liking them until they prove otherwise. Because I think that liking someone and being friends with someone are two different things, where as she thinks that they are almost exactly the same. So as of right now, I am very confused.