Idioms and Phrases with not have the heart to
not have the heart to
Be unable to bring oneself to say or do something, as in He didn't have the heart to tell her the cat had died. [Mid-1600s] Also see have a heart.
The American Heritage® Idioms Dictionary Copyright © 2002, 2001, 1995 by Houghton Mifflin Harcourt Publishing Company. Published by Houghton Mifflin Harcourt Publishing Company.