1Doing something over and over again; a somewhat formal adverb emphasizing repeated occurrence.
再三の注意にもかかわらず、彼は遅刻を繰り返した。
Despite being warned repeatedly, he kept being late.
再三の交渉の末、ようやく契約が成立した。
After repeated negotiations, the contract was finally concluded.
再三お伝えした通り、締め切りは変更できません。
As I have told you repeatedly, the deadline cannot be changed.