2 sentences for 难保 (nán​bǎo)

1. 谁也难保他明天不会变卦。

   shéi yě nán​bǎo tā míng​tiān bù huì biàn​guà.

   No one can guarantee that he won't change his mind tomorrow.

   Source: Dong Chinese Dictionary

2. 在这样的环境下，这里的古建筑恐怕难保。

   zài zhè​yàng de huán​jìng xià, zhè​lǐ de gǔ​jiàn​zhù kǒng​pà nán​bǎo.

   In such an environment, these ancient buildings will be hard to preserve.

   Source: Dong Chinese Dictionary