This question is about "Say It With Flowers".
Answer:
Because he realizes how rewarding honesty is.
Explanation:
At the beginning of the story, Teruo's motivations were centered on the fact that he had a job in floriculture, which was a pleasant environment where he kept in touch with people and flowers. However, seeing his boss's dishonesty in selling old flowers for the price of dried flowers, he changed his motivation. Now he was motivated by honesty and the gratification it caused.
