This question is asking for a general characterization of Fatima. She is one of my favorite characters from the novel because of what she stands for and represents. I also love her as a character because the initial meeting between her and Santiago makes me chuckle.

At that moment, it seemed to him that time stood still, and the Soul of the World surged within him. When he looked in to her dark eyes, and saw that her lips were poised between a laugh and silence, he learned the most important part of the language that all the world spoke—the language that everyone on earth was capable of understanding in their heart. It was love.

Readers are being presented with the mythic idea of love at first sight. I can imagine special lighting and a wind machine being used in a film version. The narrator even gives readers the standard slow motion effect. What this paragraph also tells readers is that Fatima must be gorgeous. If Santiago is willing to believe that the mere sight of her is worth giving up his journey for, she must be some amazing sight to behold. Fatima must believe in the concept of love at first sight to some degree as well, because she echoes that sentiment a bit later in the text.

"I have been waiting for you here at this oasis for a long time. I have forgotten about my past, about my traditions, and the way in which men of the desert expect women to behave. Ever since I was a child, I have dreamed that the desert would bring me a wonderful present. Now, my present has arrived, and it's you."

What her quote also tells readers is that she is patient. She's been waiting for a long time, and we will soon learn that she is willing to keep waiting in order to let Santiago find his Personal Legend. I feel it is also important to note that Fatima appears quite wise. She knows that she has to let Santiago complete this journey, or he will eventually become resentful of her. He may one day feel as if she held him back.

In "The Alchemist", Fatima is a woman of the desert.  According to the definition of that term in the novel, a woman of the desert accepts life as it comes, and she waits for her man who has gone out into the desert to return.  She represents the love between a man and a woman to Santiago.  On his journey, he has learned about the love of the Universe and the love of friendship, but it is through Fatima that he will learn the love between a husband and a wife.  She tells him that he must complete his destined dream or else he will come to resent her for staying (no matter how much he loves her now).  Once he completes his sacred purpose, she trusts that he will return to her and she will wait for him no matter how long it takes.  She is a symbol of fidelity and trust.