Greene names his heroine after a real life character Phuong who he met during his stay in Indo-China and became friends with. Though the character is named after her, but there is no similarity between Phuong of the novel and her namesake in real life.
Phuong is introduced in the novel as the mistress of the narrator, Fowler, who prepares opium for the narrator and is totally dependent on him for her livelihood. Fowler does not care for her interests at all, as she is just a tool of pleasure for him, as he says to Pyle –
“I don’t care that for her interests. You can have her interests. I only want her body. I want her in bed with me. I’d rather ruin her and sleep with her than … look after her damned interests.”
She has the dream of reaching Europe one day so that she can live a good life. With this intention she lives with Fowler as she believes that her dream will be realized one day, though she has certain doubts about it. She carries on staying with Fowler for security, but as soon as she figures out Pyle’s love for her she moves in with Pyle. Moreover, she moves in with Pyle when she finds out that Fowler has told her a lie that his wife has agreed for the divorce. Through out the novel, she remains a silent persona, whose character is not fully developed and realized by Greene. Even the choices that she makes in her life is not her own, they are decided by her elder sister.
After Pyle’s death, Phuong again moves to Fowler’s apartment and presents herself in such a way as if nothing had happened in between. But Fowler could figure out that the girl has suffered in the process, as he says – “there was no scene, no tears, just thought – the long private thought of somebody who has to alter a whole course of life.” Life may not have changed much for Fowler, but for Phuong it is rearranging her whole life once again.