To melt means to fade away slowly and disappear, like a snowman in the middle of the Sahara.
"I'm melting! I'm melting!" — Those are the feeble cries of ice cubes on a hot summer day and Wicked Witches doused with water by a meddling girl from Kansas. To melt a stick of butter into liquid form sounds like an excellent idea for your popcorn — but perhaps not for your diet. And when your puppy looks up at you with those big brown puppy eyes, your heart probably melts — even if he just ate your slippers.