come out of water是“浮出水面”的意思,
看清他的本来面目可以说成,his true colours come out of water. (他的本来面目浮出了水面)
楼上说的也对
还有其他的说法可供参考
I finally recognise what kind of person he is.
比较口语的
You have to strip away the affected manners and speech to get at the real man underneath.
比较书面化吧
中国人在翻译英语时的通病是:逐字翻译,殊不知这样翻的效果往往是中国人不会,外国人不懂。建议多看一些美语电影或英文网站之类的,这句话可以这样翻:I finally know what kind of people you are.
其实简单点用:see his true colors 完全可以。
Show his true colors!