Final answer:
In 'The Alchemist', the Alchemist and Santiago were the two people smiling after Santiago successfully turned himself into the wind; the former smiled with pride over his student's accomplishment and the latter due to achieving his personal legend.
Step-by-step explanation:
The question pertains to the novel The Alchemist by Paulo Coelho, and it asks about the reaction of certain characters when Santiago, the protagonist, accomplishes the feat of transforming himself into the wind. In the context of the story, two people were smiling after Santiago turned himself into the wind. Those two people were the Alchemist and Santiago himself. The Alchemist was smiling because he was proud of Santiago's achievement, witnessing his student realizing his potential and mastering the forces of nature. On the other side, Santiago was smiling because he had achieved the impossible, thus embracing his personal legend and the destiny he had been seeking throughout his journey.