Meaning of the word "be in someone's good books" in English

What does "be in someone's good books" mean in English? Explore the meaning, pronunciation, and specific usage of this word with Lingoland.

be in someone's good books

US /bi ɪn ˈsʌm.wʌnz ɡʊd bʊks/
UK /bi ɪn ˈsʌm.wʌnz ɡʊd bʊks/

Idiom

to be in favor with someone because you have pleased them

Example:
I'm trying to be in my boss's good books so I can get that promotion.
After helping her with the project, I'm definitely in her good books.