"Was du liebst, lass frei. Kommt es zurück, gehört es dir - für immer." "If you love, let it go. If it returns, it belongs to you - forever." Confucius
I would love to see the original text (and be able to read and understand it).
The meaning of "let it go" is clear - it doesn't make sense (and doesn't help at all - on the contrary) to try to "keep" someone who decided to go. (I even would put it narrower: when you live with someone, he/she needs this freedom too - "What do you think in this moment? Won't you put on your jacket, it looks like rain" or "I hate that bloke you go to a pub with" gives only one sort of example). You have to trust. I look with mixed feelings of pity, understanding and contempt at the selfishness of those mothers who bind their sons forever to themselves - poor things, both.
Freedom enables a person to grow. Find his/her own path in life. You get love and trust back from them - voluntarily.
A lover you have to let go in full trust if it is over, and if you let them go in peace, you'll have a friend for a lifetime. (My experience, ever).
Even a friend you have to let go sometimes - suddenly there might be a pause of some years between you - one is having a career, the other raises children, or whatsoever - and then, suddenly, they are back again.
So - this part of the quote I think I understand well, and try to live up to it. (I didn't say it is easy).
I have problems with the other part of the quote: "gehört/belongs" - in my sense of values no human being 'belongs' to somebody else. And to believe that Confucius wrote "forever" - when the 'mantra' of the Tao is all change - is not understandable to me.
Maybe the German translation is wrong. (The English above is only the mirrored translation by me - maybe there are official English translations with different content? I didn't find them.)
But I'm not in the mood to surf further through the world wide web now. The sun shines on my balcony, the swallows cut the sky screeching shrilly, the scent of my lilies is almost deafening - I drink my cup of tea -
and let it go.