We would all like our relationships with others to last and work out. Whether it's family, friends, or that special someone, we never enter it expecting or wanting it to end. We try hard to make it work, because we don't want to lose them. Yet sometimes two people are just to different for the relationship to work out. When you love someone, or even like them, you are supposed to like them for who they are, not who you want them to be. You're not going into a relationship with someone with a plan to change them into the person you want them to be.
Nevertheless, lots of people do just that. They like the other person initially of course, but there's something they see (or don't see) in them that they would like to change. That's really not how it works. You are supposed to be attracted to people you like to start off; you're not supposed to find someone and all the while be planning in your head how you would like them to be different. If you aren't pulled toward that person simply because of who they are, then they're not the one for you.
It's not that people can't be different and still be friends; lots of people have a variety of friends from all different walks of life. While your friends may be different from each other, the one thing they all need to have in common is love. We need to love our friends; simple as that. Not just like, but love. For friends are supposed to be people in your life who you can count on, who you can trust, who stand beside you through the good and bad. If they balk at the first disagreement or fight then they aren't good enough friends to keep anyways. With that love comes trust, complete and utter trust. Trust is something earned, not freely given. I'm not just talking about instinctual trust, but the kind of trust where you can tell that person anything and they will stand by you on it, even if they disagree. That is something very hard to achieve in a relationship, and if you've ever had that trust broken by someone it's all the more difficult. It takes time to feel that safe with someone, yet you sometimes just have to follow your heart and take a chance that it will work out; that your friend will always be beside you.
While it would be nice to have your beliefs confirmed, that's not always the case. Sometimes, as I was saying before, people just don't work well together. Whether it is coming from a significantly different childhood, having different cultural and religious beliefs, or simply the ever threatening "they don't love you the same way" conflict, you may just have to give up on them. While I believe deep love can conquer all obstacles, if that love isn't reciprocated than it doesn't work. To use an analogy if I may, think of a wide row boat (yes I know this has been widely used). Two people sitting side by side, each with an oar. If one of them is rowing while the other isn't, then you just keep going in circles; getting nowhere. You didn't get into the boat with them expecting to go in circles, you expected them to take the other oar and together you would get to your destination. If two people are friends but one has a mistrust of the other, you will just end up going in circles; never achieving anything.