idiom
C2
If someone is in your good books, you like them; if they are in your bad books, you are upset with them.
After helping her with the chores, I can tell I’m in her good books now.
彼女の家事を手伝った後、私は彼女の良い本の中にいることがわかります。
translation
誰かの良い/悪い本にいる