have it in one to do

have it in (one) to (do something)

To have or possess a specific skill or trait. Wow, Alice is a beautiful singer—I didn't know she had it in her to do that. Honestly, I'm not sure he has it in him to deal with this.
See also: have

have it in one to do something

to have the motivation or inspiration to do something. She just doesn't have it in her to go back home. I wanted to help out, but I just didn't have it in me.
See also: have, one