Cooper, Louise Field "Left Undone."

A poignant short story from the waning days of the Second World War which ends on a wry, humorous note. A family from Connecticut (Mr. and Mrs. Finlay, and their three children) sadly prepare for the departure of the two English children evacuees who’d lived with them in the safety of America for over four years of war. In a reflective mood thinking over the past four years, Mrs. Findlay realizes, to her horror, that one thing she has neglected to do is to explain the facts of life to the older of the English girls (16 year old Vivian Chace). The first of the story’s two climaxes occurs as the family take their charges to the Cunard piers in New York City for embarkation:
“Next morning at eleven, Mr. and Mrs. Findlay gave Vivian and Rosemary back to their compatriots. A cold, gray drizzle was falling at the entrance to the Cunard pier. The Findlays were not allowed inside, and once Vivian and Rosemary left them to go through that fateful portal, they could not come out. They all stood about in the wet for a while, trying to think of something to say, trying not to cry, looking fixedly at the other passengers and their friends. The members of the British and American armed forces that also stood about on the pavement, mounted guard in the doorway, examined passports, and could be seen moving around inside all looked to Mrs. Findlay’s anxious scrutiny more than normally bright-eyed and rapacious. Was that incipient passion or simple kindliness shining in their eyes? To her chagrin, Mrs. Findlay had to admit to herself that she couldn’t tell the difference.”
All ends well, with an uneventful (or was it?) North Atlantic crossing that is detailed by the two sisters in separate letters back to their American family.