苦心

Noun

 * 1) pains; efforts; hard work

Adverb

 * 1) with strenuous efforts; painstakingly

Etymology
From.

Noun

 * 1) pains, efforts, hard work

Derived terms

 * : taking great pains
 * : account of the hardships one has encountered

Idioms

 * : have one's labor appreciated

Verb

 * 1) make strenuous efforts, be at pains to, struggle to