It would have 'melted your heart' [=it would have filled you with compassion, sympathy, etc.] to see her lying in that hospital bed.
Her anger 'melted away' when she saw that he was truly sorry.
He seemed to 'melt into' thin air. [=he seemed to disappear]
(..) We must ride, like thundering waves under battle flag of my father. You must rest. We have rested long enough. Frost to fire, fire to frost. Iron will melt. But it will writhe inside of itself. All these years, all I've known is darkness. But I have never seen a brighter (..)2012 Snow White and the Huntsman