Break someone's heart
Definition: hurt someone, usually romantically, or to cause some great disappointment
Eat your heart out
Definition: to be jealous or envious of someone else
Follow your heart
Definition: Do what you believe is right
From the bottom of my heart
Definition: Usually used in the first person, this phrase means that you are completely sincere
Get at the heart of the matter
Definition: Discuss the main issue, concern
Have a change of heart
Definition: Change one's mind
Have a heart of gold
Definition: Be very trustworthy and well meaning
Have a heart of stone
Definition: Be cold, unforgiving
Have a heart-to-heart talk
Definition: Have an open and honest discussion with someone
Have your heart in the right place / One's heart in the right place
Definition: To mean well, have the right intentions
Know something by heart / learn something by heart
Definition: Know something such as lines in a play, or music perfectly, to be able to perform something by memory
Have one's heart set on something / set against something
Definition: Absolutely want something / Absolutely not want something
One's heart misses a beat / One's heart skips a beat
Definition: To be completely surprised by something