1. let sb. down

使失望

eg. And He has never let me down.

他也从来没有让我失望过。

eg. You desperately let me down!

你太让我失望了！

2. break one's heart

使某人心碎

eg. It would break my heart if any members of my family moved far away.

要是家里有任何人搬到远方，我会非常难过的。

eg. Some stories just break your heart on every level, like this tragic one.

有些故事会让你痛彻心扉，这像下面说的这个悲剧一样。

3. afraid of

害怕

eg. There's nothing to be afraid of.

没有什么可怕的。

eg. I'm afraid of mucking up your plan.

我担心会打乱你的计划。