を～にまかせる (wo-ni-makaseru): Leave something to; entrust
～を～にまかせる (wo-ni-makaseru)
Meaning
Leave something to; entrust
Formation and usage
N1 + を + N2 + に任せる
Notation: N = noun; V dictionary = dictionary-form verb; V stem = the stem before ます; plain clause = plain-form clause; negative stem = the form before ない. Follow the attachment shown above.
Explanation
Entrusts handling or decisions to someone; leaving an outcome to chance is a related use, not blaming someone.
Examples
会議の準備を担当者に任せた。
I left the preparations for the meeting to the person in charge.
試験の準備を担当者に任せた。
I left the preparations for the exam to the person in charge.
研修の準備を担当者に任せた。
I left the preparations for the training session to the person in charge.
発表会の準備を担当者に任せた。
I left the preparations for the presentation event to the person in charge.
面接の準備を担当者に任せた。
I left the preparations for the interview to the person in charge.
How related patterns differ
が気になる is a spontaneous concern; に気をつける is deliberate caution. に備えて prepares; に任せる entrusts. にかこつけて uses a pretext, を押して overcomes a barrier, をものともせず is undaunted, をよそに disregards, and にかまけて neglects other duties.