2 sentences for 正 (zhèng — pure/vivid)

1. 这件衣服的色儿很正。

   zhè jiàn yī​fu de shǎi er hěn zhèng.

   The color of this garment is very pure.

   Source: Dong Chinese Dictionary

2. 这件毛衣的红颜色很正，穿在身上显得皮肤很白。

   zhè jiàn máo​yī de hóng yán sè hěn zhèng, chuān zài shēn​shang xiǎn​de pí​fū hěn bái.

   The red of this sweater is a very true shade; it makes your skin look very fair when you wear it.

   Source: Dong Chinese Dictionary