Who is Fatima?
Fatima is more than Santiago's love; she is is soulmate. When the two first meet, they have an instant (and very deep) connection. She proves to be Santiago's true love and soulmate by encouraging him in his question and to follow his dream. By doing this, she passes the test of true love. She says, "If our love is part of your dream, he will come back to her once [the dream] is acheived."
She is a woman of the desert - the dry, sandy place is her home and she knows it well. She has learned the difficult lessons which life has to offer, but she has also learned that everything is connected and intertwined. She has also learned the lesson that time is eternal and connects all things. As she pushes Santiago towards his dream, she says: "those who don’t return become a part of the clouds, a part of the animals that hide in the ravines and of the water that comes from the earth. They become a part of everything….They become the Soul of the World.” This is the lesson of the Soul of the World.
The two of them are greatly rewarded for her faith and steadfastness in their love. When Santiago completes his lessons and acheives his dream of finding the treasure, he hears Fatima calling - her voice riding the wind. The novel ends with these final words: "I'm coming, Fatima."