This is the 290th most frequent Korean word.
여부를
"여부를" means "whether" or "the matter of."
"여부를" is used here to express the inquiry about the presence or absence of an action (attending) as part of a decision or condition.
그가 참석 여부를 확인하고 싶습니다.
I want to check whether he will attend or not.
"여부를" indicates the consideration of two outcomes: success or failure of the plan.
우리는 계획이 성공할 여부를 알 수 없습니다.
We cannot know whether the plan will succeed or not.
"여부를" pertains to the dichotomy of outcomes, here specifying the result of passing or failing.