I think we had agreed that you would do ○○ on Sunday evening...
I thought you had promised that you would do ○○ on Sunday evening...
ご質問ありがとうございます。
① "I think we had agreed that you would do ○○ on Sunday evening..."=「日曜の夕方に○○を貴方がするということになっていたと思うけど...」
② "I thought you had promised that you would do ○○ on Sunday evening..."=「あなたが日曜の夕方に○○をするという約束をしたと思っていたけど...」
ご参考に。
I believe we had agreed that you will ... on Sunday afternoon.
こんにちは。
さまざまな言い方ができると思いますが、下記のような英語表現はいかがでしょうか:
I believe we had agreed that you will ... on Sunday afternoon.
日曜夕方に貴方に〇〇してもらう約束だったと思うけど…
I believe ... は「〜だと思いますが」のような意味で少し丁寧な言い方です。
ぜひ参考にしてください。