One may feel heartbreak when a (romantic) relationship comes to an end or when one has been cheated on etc. You cannot think about anything except for the awful pain you feel and how much you hate the person for leaving you, and at the same time desperately want them back.
Heartbreak literally feels like someone stabbing a knife into your chest and twisting it repeteadly.
Essentially she makes you feel like shit unworthy to tread the face of this earth or even gaze upon her divine form.
(verb): He was heartbroken after he did not recieve the part in the play.
2. Especially damaging the first time, and even worse if you're old enough to have known better.
3. That which leaves a constant residual heartache