~에 심혈을 기울이다 · 심혈을 기울여 만든 (+noun)
to put one's heart and soul into, to pour all one's effort into
Example
그는 이 작품에 3년 동안 심혈을 기울였어요.
He poured his heart and soul into this work for three years.
Word parts
심 heart+혈 blood
Literally 'tilt your heart's blood' toward something — giving it everything.