You can take his word for it. He has always been on the up and up.

你可以相信他的话, 他一向老实可靠.

《现代汉英综合大词典》

I'm a pretty good judge of men. If you're honest and on the up and up, I'll be able to tell it.

我看人很准的。你要是诚实正派，我能看出来的。

柯林斯例句

From now on everything is on the up and up.

从现在起,一切事情都会起来的.

互联网

Business is on the up - and - up .

生意越做 越 大.

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