口中有蜜，心中有毒。

Honey in the mouth and poison in the heart.

Source: Tatoeba

Sentence Composition

1 口 kǒu
  1. mouth
  2. classifier for things with mouths (people, domestic animals, cannons, wells etc)
  3. classifier for bites or mouthfuls
2 中有 zhōngyǒu
  1. (Buddhism) bardo
  2. bardo
3 蜜 mì honey
4 心中 xīnzhōng
  1. central point
  2. in one's thoughts
  3. in one's heart
5 有毒 yǒudú poisonous