When Désirée confronts Armand, she and Armand both believe that she is the parent with Black ancestry and therefore the reason their son is mixed-race. Armand acts on this assumption by rejecting Désirée and telling her to leave their home:
He thought Almighty God had dealt cruelly and unjustly with him; and felt, somehow, that he was paying Him back in kind when he stabbed thus into his wife’s soul. Moreover he no longer loved her, because of the unconscious injury she had brought upon his home and his name.
Even though Armand previously insisted that Désirée’s racial background was of no importance to him, he behaves in a very racist manner when he suddenly thinks that she is Black. His complete rejection of Désirée and their life together sets up the story’s final reveal. After Désirée disappears, he burns her clothing and a series of letters written during the beginning of their relationship. At the bottom of the pile, he finds something unexpected: a letter from his mother to his father. It says:
“I thank the good God for having so arranged our lives that our dear Armand will never know his mother, who adores him, belongs to the race that is cursed with the brand of slavery.”
Armand’s treatment of Désirée is completely transformed by this news because the outcome of the situation is the exact opposite of what both he and the reader expect. The story's use of situational irony perfectly punctuates the hypocrisy of Armand’s actions. He punished Désirée for something that ultimately had nothing to do with her and everything to do with him. It’s a sharp twist on the ugly drama that directly preceded this moment. Chopin ends the short story before describing Armand’s reaction, so the reader is left only with an impression of his grave mistake and the ultimate reveal of his identity.
