Della is upset . Only having $ 1.87 to spend on a Christmas gift for her husband she cries about not being able to afford anything nice.
You cut your hair!!!
suddenly she remembers that she carries something that is very valuable not only to her but to her husband, her hair. Therefore she decides she must sell it to be able to afford what her husband deserves.
but i sold my watch for your gift
I sold it for your gift! A fob chain
At the store she is able to sell her hair for $20.00 which is perfect because she is able to buy her husband a platinum fob chain for his watch that he valued dearly.
Once she returned home anxiety consumed her. She hoped that her husband wouldn't see her any differently than before. And when her husband returned home he was shocked to see his wife without her precious hair.
Della begged her husband to still find her attractive and remember that she did it for him . Jim comforted her and told her that her hair didn't make her any less than the woman he married. But he sacrificed his watch to buy her a gift that was for something she sacrificed for him. He had bought her hair combs.
Jim internally swooned with gratitude and love for his wife. Instead of working his wife up again , he decided to comfort her and asked her to put the presents to the side. Their love and sacrifice for each other made up for the things that they had lost.