很抱歉让你失望，但我恐怕还是不能来。

I'm sorry to ___disappoint you, but I'm afraid I can't come after all.

我们不想让粉丝失望。

We don't want to ___disappoint the fans.

我一直和小孩相处得很好，我肯定不会让你失望。

I've always got along very well with little kids and I'm sure I won't ___disappoint you.