Although Lakshmi doesn't realize it at the time, Shahanna is one of the first girls who greets her at Happiness House. Shahanna is pretty with nut-brown skin, and from Nepal just like Lakshmi. In fact, one reason Shahanna might have befriended Lakshmi in the first place is because they speak the same language.
Throughout Lakshmi's tenure at the brothel, Shahanna serves as Lakshmi's guide and confidante. When Lakshmi is first getting prepared for her work in the brothel—even before she realizes what kind of work she must do—Shahanna tries to reach out to her:
The dark-skinned girl starts to answer, but the frowning one tells her to shush. (68.ACityGirl.7)
Shahanna, to be clear, is the "dark-skinned girl."
And when Lakshmi is locked in the small room for days on end and starved, it is Shahanna who brings her a much needed cup of tea. Though the words Shahanna speaks are meant to convince Lakshmi that the brothel isn't as bad as the streets—a tough message to buy into, for sure—she does so with kind intentions. Not convinced? Shahanna takes the risk of surreptitiously bringing Lakshmi a condom, which is forbidden by Mumtaz (and as such certain to get both of them in deep trouble).
Because of these actions, the impression we form of Shahanna is that she is compassionate and that she seeks friendship—and as Lakshmi settles into life in the brothel, Shahanna becomes her closest friend. Shahanna is the one who explains each person's story and tells Lakshmi the rules of the house so Lakshmi can stay out of trouble.
Although we learn how the other women in the brothel came to be there, we never know more about Shahanna's background except that she's from Nepal. There are a number of reasons McCormick might have left this information out, but we think it could very well be to show that—despite having a close friend—Lakshmi is still deeply isolated at Happiness House. Without much information about Shahanna, she remains flat for us as readers, and in this way Lakshmi sort of stands alone for us. That's just one interpretation, though. What do you think?