Mr and I will be delighted to dine with you on Friday, the first ot April at eight o'clock. How very nice of you to invite us!
We are both looking forward with great pleasure to seeing you and Mr ... again.
Sincerely yours,
Refusal
Dear Mrs ...
I cannot tell you how sorry I am that we cannot dine with you on Friday, the first of April. Unfortunately, my husband is on a business mission now, and he will be back only on Sunday, too late for your dinner party. That is why we are unable to accept your kind invitation. It was very kind of you to ask us; and I know Mr ... will be as sorry as I am to miss an evening with you and Mr ... .