On my point of view this short story is organizedinto two important parts. Now i am carring out both parts:

In the first part the function is to introduces the story, all the protagonists and the backgrounds: Eveline has doubts about the wisdom(saggezza) of her intentions, but it seems almost certain at first that she has the energy and determination to keep her agreement to explore another life with Frank; and, when the time comes to leave home, she is shown driven by a sudden(improvviso) impulse of terror to escape her past, in the conviction that Frank would save her.

In the second part of the story we can see that the promise that she had made to her mother as she dying "to keep the home together as long as she could" will paralyse her wish to escape.