Koyuki's worried about his future. He wants to be a teacher, but he's not sure he can do it.
If it is, then it's better that you quit.
إذا كان كذلك فمن الأفضل أن تتوقّف
Wenn das so ist,
dann lass es lieber bleiben.
Se è così, faresti meglio ad andartene.
Se for assim, é mesmo melhor desistir.