idiom
C2
If you do something to/till/until the bitter end, you keep going until it's completely done, even if it's hard.
I promised to stick with the project until the bitter end, no matter how tough it got.
나는 프로젝트가 아무리 힘들어도 마지막까지 함께하겠다고 약속했습니다.
translation
쓰라린 결말까지