beauty is in the eye of the beholder

 情人眼里出西施

►含义：

used to say that different people have different ideas about what is beautiful

这句话用来表示不同人对美的定义是不同的（美是个人的主观感受）

►例句：

I don't understand how he can think she is good-looking, but beauty is in the eye of the beholder. 

我不知道他怎么会认为她好看呢，但是情人眼里出西施。

►对话：

A:I always thought Johnny was pretty good looking, but his girlfriend, uh, not so much....

我经常在想，Johnny 这么帅，但女朋友，呃，不太…

B:Well, beauty is in the eye of the beholder I guess. Johnny probably sees something we can't see. 

情人眼里出西施吧，可能 Johnny 看到了我们看不到的东西。

►额外收获： 

1.different people have different ideas about…：对于…仁者见仁智者见智

2.good-looking：好看的