询根问底
xún​gēn​wèn​dǐ

to get to the bottom of something

  1. 询 詢 xún verbnoun
    to inquire
    (bound form) to ask about; to inquire or seek advice, as in 询问 xún​wèn or 咨询 zī​xún
  2. 根 gēn adverbnoun
    source
    (bound form) the origin, cause, or source of a situation or problem
  3. 问 問 wèn verb
    to ask
    to ask; to inquire; to request an answer from someone
  4. 底 dǐ adverb
    ins and outs
    The truth behind a matter; the underlying details or background information