Explain the huge mistake Trysdale made. When does he find this out?
In O. Henry's short story "The Cactus" the man named Trysdale allows the girl he is in love with to believe that, among all his many other accomplishments for which she admires him, he knows the Spanish language thoroughly.
She had always insisted upon placing him upon a pedestal, and he had accepted her homage with royal grandeur. It had been a very sweet incense that she had burned before him; so modest (he told himself); so childlike and worshipful, and (he would once have sworn) so sincere. She had invested him with an almost supernatural number of high attributes and excellencies and talents, and he had absorbed the oblation as a desert drinks the rain that can coax from it no promise of blossom or fruit.
When he proposes marriage, she does not give him an immediate answer but tells him she will send her answer tomorrow. He doesn't hear from her the next day but receives a strange-looking cactus plant from her, delivered by messenger. He waits and waits for her response. He encounters her one evening at a social affair and she assumes a cold and offended manner. Evidently she had been expecting him to greet her with more of a show of affection. On his part, however, he did not know how to behave toward her because he was still waiting for some response to his marriage proposal.
With womanly swiftness she took her cue from his manner, and turned to snow and ice.
He can't understand what he did to offend her. Shortly afterward she marries another man in an elaborate church ceremony. Trysdale attends as a guest and is grieved to see the girl he loved being married to another man. It is not until some time after the wedding that Trysdale learns that the cactus plant the girl sent him contained an implicit acceptance of his proposal. The girl's brother tells him:
"Yes. The natives imagine the leaves are reaching out and beckoning to you. They call it by this name--Ventomarme. Name means in English, 'Come and take me.'"
Trysdale realizes with horror that he had made a terrible mistake in pretending that he understood the Spanish language. Since he hadn't gone to her when he received the cactus with the trembling, beckoning leaves, she assumed that he was not truly in love with her, and she had accepted the proposal of another suitor. He should have understood the name Ventomarme. It is a mistake to try to deceive the person you love.