3 sentences

1. 这里的山泉水非常纯净。

   zhè​lǐ de shān​quán​shuǐ fēi​cháng chún​jìng.

   The mountain spring water here is very pure.

   Source: Dong Chinese Dictionary

2. 空气非常纯净。

   kōng​qì fēi​cháng chún​jìng.

   The air is very pure.

   Source: OpenSubtitles

3. 那个孩子的眼神非常纯净。

   nà gè hái​zi de yǎn​shén fēi​cháng chún​jìng.

   The child's eyes are very pure.

   Source: Dong Chinese Dictionary