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]
(..) bring out these bad boys! It gets ugly! - What are you doing? - Stay back! If I stare at the lock really hard, it'll burst into flames and melt. Now I'm concerned on a number of levels. - Easy, watch! Watch it those! - I'm good. We gotta go. Intruders! Hey! Slow down you screwy (..)2008 Bolt