苦心（くしん）
苦心 (费心) · noun · JLPT N2
Examples
長年の苦心の末、ついに新しい技術を完成させることができた。
After many years of painstaking effort, we were finally able to complete the new technology.
Practise the thinking. Keep the judgement.
Practise the thinking. Keep the judgement.
苦心 (费心) · noun · JLPT N2
長年の苦心の末、ついに新しい技術を完成させることができた。
After many years of painstaking effort, we were finally able to complete the new technology.