So, it's likely you will never met the one. But, there will be many people who fit into your core qualities that will never change. Everyone's not static, so obviously we change our smaller qualities, and other's too. But, the person might try to change to your likes, to your qualities. And you might too. It's that desire to fill the other's needs, that makes a long relationship.
Let's say, I like people who light, brown eyes. I find a nice girl who has light brown eyes, fits my core qualities, and coincidentally, likes me too. We have a long relationship. In that long relationship, I might change my opinions, and find girls with piercing blue eyes better than light brown eyes. But that doesn't mean that I will automatically hate the girl I'm currently with. Sure, her eyes won't be as appealing, but I still like her for her core qualities. Our opinions might change, but the core qualities won't change.