知人善任

zhīrénshànrèn
(idiom) expert at appointing people according to their abilities; to put the right people in the right places

CEDICT

to know one's subordinates well enough to assign them jobs commensurate with their abilities

Wiktionary

能識別、拔擢人才，並能依據其專長而加以任用使能發揮所長。

重編國語辭典

Entry Composition

1 知人 zhīrén
  1. (archaic) to be an insightful and astute judge of character
  2. to be an insightful and astute judge of character
2 善 shàn
  1. good (virtuous)
  2. benevolent
  3. well-disposed
  4. good at sth
  5. to improve or perfect
3 任 rèn
  1. to assign
  2. to appoint
  3. to take up a post
  4. office
  5. responsibility
  6. to let
  7. to allow
  8. to give free rein to
  9. no matter (how, what etc)
  10. classifier for terms served in office, or for spouses, girlfriends etc (as in 前任男友)