Dear Miss Woodhouse,
I wanted to thank you for your kind assistance during the incident in Potions class. Your fine memory for Donne was crucial in helping me ward off the effects of the potion, and I am very much in your debt. I apologise if I may have said anything to shock or offend -- my memories of what I did and said are somewhat hazy, although sadly the memories of the War are clearer than they have been in years. I hope that you are well yourself.
Sincerely,
Lord Peter Wimsey