It's your cousin Mrs. Landis, madame.
4 seconds sound clip from the After the Thin Man (1936) movie soundboard.
You can hear this line at 00:13:46 in the DVD version of the movie.
Quote context
[...]
- Good-bye, Mrs. Charles, I'll see you next year.
- She expects you, too, Mr. Charles.
- Me?
- There must be some mistake. She wouldn't want you.
- No.
- Tell her that I lost a collar button in New York and we've got to go look for it.
- It's your cousin Mrs. Landis, madame.
- Oh, thank heavens it isn't aunt Katherine.
- I wouldn't go through that again if you had twice as much money.
[...]