to thank one―offer one's thanks―tender one's thanks―return one thanks―express one's thanks―express one's gratitude―acknowledge a favour お礼を言う - 斎藤和英大辞典
Zoisite, I will return the favour someday! ゾイサイト... 借りは必ず返す! - 映画・海外ドラマ英語字幕翻訳辞書
to express one's gratitude―express one's thanks―offer one's thanks―tender one's thanks―return one thanks―thank one―acknowledge a favour 礼を言う、礼を述べる - 斎藤和英大辞典
Should I return the favour? 奪い返しますが よろしいですか? - 映画・海外ドラマ英語字幕翻訳辞書
a favour which one should return 報いなければならない,義理のある恩 - EDR日英対訳辞書
a secret or indirect payment made in return for a business favour, such as a payment to a radio broadcaster so that he/she will use his/her influence to promote one's cause
取り引きで,事を有利に運ぶため,裏でやりとりする金 - EDR日英対訳辞書