spare no effort
He spares no efforts to help the rich widow (X window X) with a view to cheating...
I always spare no efforts to finish my work mission my supervisor had asked me to complete. 我總是(不吝惜/不放棄)努力完成我的(監督員/上司)要求我完成工作的使命。
... can devote myself to my country and spare no efforts to serve our people in the near future, and no.... Teacher are those who always take no bother to cope with students' matters...