Is the couple's love believable? Is the story's ending happy?
The answer to your first question would be a matter of opinion. Take a look at the evidence of caring and affection between Jim and Della, then decide if you think that their love is believable.
- Della feels a great sense of sadness when she realizes how little money she has to buy a Christmas gift for Jim.
- Della is willing to sacrifice her beautiful hair in order to purchase a special gift for Jim.
- When Jim comes home from work, he is usually "greatly hugged" by Della.
- Jim finds Della's long hair to be very beautiful and he values it.
- Della says to Jim, "Nobody could ever count my love for you."
- Jim reassures Della after she cuts her hair:
"I don't think there's anything in the way of a haircut or a shave or a shampoo that could make me like my girl any less."
- Jim sells his prized watch to buy combs for Della.
O. Henry did intend for the ending of the story to be happy. Della and Jim have experienced their love for one another because of the sacrifice of their prized possessions. Jim and Della are described as "the wisest."