As a form of love, compassion allows for unconditional acceptance of a person, situation, or personal experience. And the more difference and separation between us there is, the more compassion is needed.
People don't believe you love them, because they don't believe they can be loved. The problem is, they won't tell you that. They might not even know that. Don't you ever, ever, think that there's something wrong with you. They accept the love they think they deserve.