also: おまちどうさま
sorry to have kept you waiting
A polite set phrase used when you have made someone wait. Often said upon arriving late or when finally attending to someone.
遅くなってすみません、お待ちどおさま。
Sorry I'm late; thank you for waiting.
お待ちどおさま、すぐご案内します。
Sorry to have kept you waiting; I'll show you in right away.