本ほん気きを出だす

expression, godan verb (-su)

make a serious effort; get serious; put one's heart into it

Used when someone stops holding back and starts trying earnestly, often after a period of casual or half-hearted effort.

• そろそろ本ほん気きを出だして勉べん強きょうしないと、試し験けんに落おちるよ。

  If you don't start studying seriously soon, you'll fail the exam.

• 彼かれはここぞというときに本ほん気きを出だすタイプだ。

  He's the type who gets serious when it really counts.