Read this characterization of Della from "The Gift of the Magi."Then she heard his step on the stair away down on the first flight, and she turned white for just a moment.

Della turns white when she hears Jim coming upstairs, just after she has sold her hair. The sudden change in her expression suggests she is anxious about how he will react when he sees her, so the best choice is “is afraid of Jim’s reaction.”

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