眼不见，心不想。

Out of sight, out of mind.

Source: Tatoeba

Sentence Composition

1 眼 yǎn
  1. (often used with 一 yī) a look; a glance
  2. small hole
  3. (bound form) salient point
  4. classifier for wells, cave-dwellings etc

classifiers: 隻, 雙
2 不见 bùjiàn
  1. not to see
  2. not to meet
  3. to have disappeared
  4. to be missing
3 心 xīn
  1. heart
  2. mind
  3. intention
  4. center
  5. core

classifiers: 顆, 個
4 不想 bùxiǎng unexpectedly; to one's surprise