Let go if he/she wants to, you worth more than that.
他要走就让他走, 你比这值得更多。

Let go if he/she wants to, he/she does not deserve you..
他要走就让他走, 他不配你。

Let go if he/she wants to, he/ she wasn't good enough for you.
他要走就让他走, 他配不上你。

Let go if he/she wants to, you deserve better. (这个最常用, 最自然。)
他要走就让他走, 你应该拥有更好的。

希望能帮上忙, 支持学习, 欢迎追问