他说，这个标题应该改为“日本人民对失望无知无觉的本领如此惊人”。

The headline, he said, should have read: “The Japanese people's amazing inability to be disappointed”.

youdao

你本该接受的。我对你感到失望。

You should have accepted that. I'm disappointed in you.

《柯林斯英汉双解大词典》

我对自己感到非常失望。

I was very disappointed with myself.

《牛津词典》

We could no longer be disappointed, because to be disappointed in something presupposes that it could've been some other way.

我们不会再感到失望，因为对某些事情失望就表明,事情可以是另一个样子。

耶鲁公开课 - 死亡课程节选

and I was really disappointed with the results.

对自己的成绩感到很失望。

I think 实战 - SpeakingMax英语口语达人

You have to choose. Well, critics took it fairly straightforwardly as the account of a life and in that sense, taking it that way, some of them were a little disappointed with what they held in their hands.

你必须做出取舍,批评家十分直截了当地，把它看成是生活的流水帐,因此有些人会对他们手中的书稍有失望。

耶鲁公开课 - 1945年后的美国小说课程节选