我不得不承认我真的很喜欢他。

Wǒ bùdébù chéngrèn wǒ zhēnde hěn xǐhuān tā.

I can't deny, I really like him.

我不得不佩服他的勇气。

Wǒ bùdébù pèifú tāde yǒngqì.

I can't help but admire his courage.

下大雨了，我们不得不取消比赛。

Xià dàyǔ le, wǒmen bùdébù qǔxiāo bǐsài.

It rained heavily, so we had no choice but to cancel the match.