harden (oneself) to (something)
To ready or prepare oneself, often emotionally, for a difficult or unpleasant experience. How can I, as a therapist, ever harden myself to the pain of others? We all need to harden ourselves to the seriousness of Aunt Louise's diagnosis.
harden oneself to something
Fig. to make oneself capable of bearing something unpleasant. You will have to learn to harden yourself to tragedies like this. They happen every day in a hospital. She had learned to harden herself to the kinds of poverty she had to work in.