You don't just throw around the words so sweet, you don't just say them to everyone you meet. You'll build them up, "finally someone cares" and then, to find out no, he/she didn't really.
You don't say these words, just cause you feel like it, just cause you think they'd make anyone feel good. You don't just say it, for the sake of it.
you say it with heart, with feeling, with truth, honesty and everything in between. you say it cause you mean it, and you want your sweetheart to believe it.