"Jie Yin could have become a saint on his own, he didn't necessarily need to lean completely on his teacher, but Cundi definitely had no hope on his own. Therefore, Cundi could dieheartedly work for their teacher, but Jie Yin couldn't, he wasn't content. This is understandable - if I were Jie Yin, I wouldn't be content either."
Accepting that one cannot accomplish something is not difficult.
The most difficult thing to accept is that I could have.
But because of various external reasons, I gave up.