“不用你来”用英文怎么翻译简单好些呢？

leave it to me!!!!!!!!
放着我来！！！！！！！！！
或者 I can handle that
我自己能行

同意 ljwyslf 的，但通常我们都会加多一句：
It's ok, I can manage it by myself. Thank you.

没关系，我自己来吧。谢谢你。

It's none of your business.也就是不关你的事的意思。

i can manage /do it myself
i can manage /do it on my own

I'll do.
换过来说好一点罢，直接说我来做

不客气的：It's none of your business！
客气的： I can manage it
Ican do it myself