I tried to reassure her, "Don't worry about it. We won't let it happen again."

我尽力使她安心，“别担心，我们不会允许它再发生的。”

《柯林斯英汉双解大词典》

I've spoken to Ed about it and he's promised not to let it happen again.

我已经同埃德谈过了，他答应不让这种事情再次发生。

《牛津词典》

Don't let it happen.

永远不要让这种事情发生。

youdao

It's the venom. You have to make a choice.You could let the change happen.

VOA: standard.other

Don't let it happen to me.

不要折磨我。

耶鲁公开课 - 死亡课程节选

And yeah, I know you know how to do it, but let's think about what might happen if I wanted to do that.

对，我知道你们知道该怎么做，那么让我们看看如果我,想要完成的话会发生什么。

麻省理工公开课 - 计算机科学及编程导论课程节选

Players that get to play ... grab a hold of it and let it happen.

WSJ: Relaxed Bruins look to finish Rangers in Game 4

And on days such as this, we resolve to never let it happen again.

WHITEHOUSE: President Obama Bestows Presidential Unit Citation on the Blackhorse Regiment | The White House

Instead of pausing to think about change, we just let it happen to us.

FORBES: Slowing Down to Go Fast