idioms heart 7 cold-hearted (cruel, uncaring, unfeeling): He became a cold hearted killer consequently.
hand on heart (swear that something is true): Are you telling me, hand on heart, that you will never read my private messages?
harden your heart (make yourself stop having friendly feelings): She finally harden her heart and tell him to leave.
heartfelt (strongly felt, sincere): They also sent a heartfelt message of thanks to everyone who helped.
heartsick (very depressed or unhappy):
Heartless (uncaring, inconsiderate): A heartless thief stole his wheelchair while he was home.