"Warm River" is short love story by Erskine Caldwell, included in the collection We Are the Living (1933).
Richard, the protagonist, crosses in the night a dangerous footbridge in the mountains and arrives at a house where a girl named Gretchen is eagerly waiting for him.
As gradually becomes clear, Richard's original intention in coming there was to have casual sex with Gretchen and go away in the morning, possibly never to see her again.
Therefore, he declines Gretchen's invitation to kiss her, goes chastely to his room and asks her to wake him up in time catch his train in the morning.
Opening the door quietly, he sees Gretchen kneeling near her bed, praying and crying.