After Tish loses her virginity to Fonny, the couple returns to Tish's family home to tell her parents they intend to marry. Sharon, ever accepting and understanding, deliberates for a moment but then seems pleased by the arrangement. While she thinks, though, Tish describes her appearance using an oxymoron:
"You going to marry Fonny. All right. When I really think about it"—and now she paused, and, in a way, she was no longer Sharon, my mother, but someone else; but that someone else was, precisely, my mother, Sharon—"I guess I'm real pleased." She leaned back, arms folded, looking away, thinking ahead. "Yeah. He's real. He's a man."
While she thinks, Sharon looks at once like herself but also like someone else. This oxymoron shows how Tish feels scared and alienated from reality at this point in the novel. She has noted how she felt "everything changed" when she had sex with Fonny, and now she fears that her mother will not support her. This causes her mother to briefly look like a different person—but when Tish realizes Sharon will, as always, be caring and accepting, she looks like herself again.
As a consequence of the first-person narration in the novel, it is not clear exactly what Sharon thinks here, or why her face appears to change. Sharon appears to consider what might happen with Fonny in the future, perhaps thinking back to failed relationships she had with men in the past, described in flashbacks elsewhere in the book. However, this is intentionally ambiguous, and the reader is left only with Tish's confused reaction.