harden your heart
US /ˈhɑːr.dən jʊər hɑːrt/
UK /ˈhɑːr.dən jʊər hɑːrt/
1.
to become less sympathetic or emotionally unresponsive to others' suffering or pleas
:
•
She tried to harden her heart to his pleas, but she couldn't.
•
You must harden your heart if you want to survive in this business.