Fetching details from the dictionary...

again and again; repeatedly
再三注意されても彼は同じ失敗を繰り返す。
Even after being warned repeatedly, he keeps making the same mistakes.
再三確認したにもかかわらず間違えた。
I made a mistake despite checking repeatedly.
母に再三言われてやっと部屋を片付けた。
I finally cleaned my room after my mother told me repeatedly.