I'm sorry I let you down.

对不起，我令你失望了。

youdao

I'm sorry I let you down.

很抱歉我让你失望了！

youdao

I am most awfully sorry to let you down.

叫您失望我感到非常抱歉。

youdao

I am terribly sorry if I let you down.

让你失望了，对此我非常抱歉。

youdao

I am sorry to let you down.

对不起，让你失望了。

youdao

I did promise, and I did let you down. I'm sorry.

我是发过誓，我也让你失望了，我对不住你。

youdao

I did promise, and I did let you down. I'm sorry.

我是发过誓，我也让你失望了，我对不住你。

youdao