What is the difference between "I like you" and "I love you"? Beautifully answered by Buddha. When you like a flower, you just pluck it. But when you love a flower, you water it daily. One who understands this, understands life.
And that is the saddest truth of all - when we let others tell us what love is instead of deciding it by ourselves, never questioning whether they truly love us, or if they even know how to love themselves or others.