I have to admit that I used to think English is a very straightforward language without the subtle meaning behind the words until I encountered this song , a very gentle way to express deep sadness and regret for love lost. My heart broke while I was listening to it and this song reminded me of another song 《我终于失去了你》. They both convey the same feeling, albeit the way singers expressed it differently. All of sudden, the vibrations of two songs echoed and merged with each other and the best translation of “let her go” is ”我终于失去了你”. I think the lesson both singers can learn or we all can learn is “劝君莫惜金缕衣，劝君惜取少年时。花开堪折直须折，莫待无花空折枝。”
P.S. I rushed to make this piece to meet the deadline. I would like to call for the translation for the ancient peom:
劝君莫惜金缕衣，劝君惜取少年时。花开堪折直须折，莫待无花空折枝。
Let her go