Lyric discussion by Burn_It_Down 

Cover art for Heart of Fire lyrics by Innerpartysystem

I reckon it's about a guy who made a girl fall in love with him even though he didn't care about her that much. And he's running it through now and saying how he just said everything she ever wanted to make her happy and now it's gone too far he is revealing what really went on.

It's a sad thing that happens and it's something we all do. Hearts on fire seems to be the metaphor for use just bruning people emotions.