但更痛苦的是爱一个人。

But what is more painful is to love someone.

youdao

但更痛苦的是爱一个人却没有勇气让那个人知道你的感受。

But what is more painful is to love someone and never find the courage to let that person know how you feel.

youdao

爱一个人而那个人不爱你是很让人难受的，但更痛苦的是，爱一个人却永远都没有勇气告诉她。

It is very painful that you love one person while the person does not love to, but it is more painful that ou have no courage to tell him or hei your feeling.

youdao