You have nothing to lose by telling the truth.
你讲真话是不会吃亏的。
I'd have nothing to do with him, if I were you.
如果我是你，我就不会跟他有任何瓜葛。
'I have nothing to say to you,' she said icily.
“我对你没什么可说的。”她冷冷地说。
If you take my advice you'll have nothing more to do with him.
你要是听我的劝告，就不要再和他有什么瓜葛。