用心良苦

to ponder earnestly / to give a lot of thought to sth

to use / to employ / to have to / to eat or drink / expense or outlay / usefulness / hence / therefore

motive / intention / to be diligent or attentive / careful

heart / mind / intention / center / core / CL:顆|颗[ke1],個|个[ge4]

good / very / very much

bitter / hardship / pain / to suffer / to bring suffering to / painstakingly