Final answer:
In the novel 'The Alchemist' by Paulo Coelho, Santiago finds a love interest named Fatima when he follows his new friend into the marketplace.
Step-by-step explanation:
When Santiago follows his new friend into the marketplace in the novel, 'The Alchemist' by Paulo Coelho, he finds a love interest named Fatima. While in the marketplace, Santiago catches sight of a beautiful girl named Fatima and becomes infatuated with her. This encounter leads to a significant plot development in the story.