I am looking for the story in which Hurcule Poirot gives advice to a girl who is wondering wether or not to marry a certain man.

I am looking for the story in which Hurcule Poirot gives advice to a girl who is wondering wether or not to marry a certain man. He gives her three questions to answer to determine wether or not the match is a good one.
1. do you both prefer to sleep with the bedroom window open or closed?
2. are you both early risers or late nighters?
And, 3 is the question that I cannot remember.

I seem to recall that the setting was at a hotel while he was on a holiday.
I cannot remember if it was a short story or a novel.

Does anyone recall the story?
Thanks,
SRO