不厌其烦

不厌其烦	bù yàn qí fán	not to mind taking all the trouble (idiom) / to take great pains / to be very patient
不	bù	no; not so / (bound form) not; un-
不厌	bù yàn	not to tire of / not to object to
厌	yàn	(bound form) to loathe; to be fed up with / (literary) to satiate; to satisfy
其	qí	his / her / its / their / that / such / it (refers to sth preceding it)
烦	fán	to feel vexed / to bother / to trouble / superfluous and confusing / edgy