This is the 8638th most frequent Korean word.
가야하나
"Do I have to go?"
The phrase '가야하나' is used here to express contemplation or uncertainty about the necessity of going (가야) to the school.
내일 학교에 가야하나 고민 중이에요.
I am wondering if I should go to school tomorrow.
In this context, '가야하나' is used as a rhetorical question to oneself about whether or not to proceed with going (가야).
산을 오르려면 더 많은 준비가 필요하다고? 가야하나?
They say more preparation is needed to climb the mountain? Should I still go?
Here, '가야하나' reflects an internal contemplation, questioning the necessity or desirability of attending (가야) the event.