There are lots of endings in any collection of short stories—14 in this one, to be exact—so we're going to look at the bigger picture here. Walker ends her book with "Source," the story of two friends—one Black (Irene), one biracial (Anastasia)—and how they struggle with their identities.
The two women have to do a little living before they begin to see themselves and each other with clarity. That clarity comes at a price: Irene has to acknowledge that she's been a jerk, and Anastasia has to make a hard choice about her racial identity.
It's possible that Walker randomly placed "Source" at the end of this collection, but it doesn't feel that way. (And how many authors just do things at random?) For one thing, it's a chunky piece, crossing the finish line only after 30 pages. It's literally a big ol' anchor at the end of the book.
"Source" also feels like the most developed story in the book—especially after the fragmented "Advancing Luna—and Ida B. Wells," which also traces the arc of friendship between two women who struggle with issues of race.
But unlike the women in that doomed friendship, Anastasia and Irene land on their feet and usher us out of a book full of difficult relationships with a sense that friendship can prevail—especially when resilient, determined women are involved.