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.
Farlex Dictionary of Idioms. © 2022 Farlex, Inc, all rights reserved.
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.
McGraw-Hill Dictionary of American Idioms and Phrasal Verbs. © 2002 by The McGraw-Hill Companies, Inc.