1
to leave (a matter, decision, etc. to someone);to entrust (to someone);to entrust (someone) with
最終決定は彼に任せた。
We left the final decision to him.
2
to leave (to chance, one's imagination, etc.);to let (take its own course);to let (happen);to give (oneself to something)
ご想像にお任せします。
I'll leave it up to your imagination.
3
to use (money, strength, spare time, etc.) to the full;to use freely;to use without reserve
as ...に任せて
Other forms
委せる 【まかせる】 (rarely used kanji form)