Hermila (Hermila Guedes) spends most of “Love for Sale” hawking raffle tickets for “a night in paradise.” She’s a perfectly proportioned single mother, with shapely cheekbones and sharp eyebrows, and she doesn’t have a whole lot of trouble finding customers.

But when word of her business venture gets around her hometown of Iguatu, in northeastern Brazil — to which she has returned, penniless and unaccompanied by her disinterested husband, after two years in São Paulo — it meets with stern disapproval. Friends warn that she might go to jail. Her grandmother kicks her out of the house. Another woman threatens to beat her face in. But Hermila goes ahead with it anyway.

The Brazilian writer-director Karim Ainouz — whose last film, “Madame Satã,” was a lovingly drawn portrait of a bar-fighting, spotlight-snatching outlaw transvestite — seems to be drawn to characters who aren’t easily swayed by the opinions of others. But one of the many pleasant surprises in “Love for Sale,” which begins a two-week run at Film Forum today, is the deep sympathy Mr. Ainouz reserves for those concerned bystanders. Hermila’s secretly lesbian aunt (Maria Menezes), hard-working grandmother (Zezita Matos), and tentative new lover (João Miguel) may be less romantic — and less photogenic — than she is, but the acutely drawn relationships on display in this understated film remind us that they are no less human.

While Hermila’s aunt and grandmother care for her infant son, she finds sporadic work cleaning cars and hotel rooms. She also finds a new friend in a prostitute named Georgina (Georgina Castro). Hermila, who wants desperately to get out of Iguatu, is drawn to Georgina’s easy nature but also covets her independence and steady income. Eventually she decides to fund her escape by offering herself, lottery-style, for a single night to one lucky winner.

Hermila’s aunt is worried it will lead to trouble; her grandmother, when she finds out later, is furious. Both reactions are perfectly understandable, and Mr. Ainouz subtly makes clear that they are rooted in their love for Hermila. With the exception of the deadbeat father of Hermila’s child, “Love for Sale” has no conventional antagonists. Instead, the drama in this low-key film emerges slowly and naturally, as if seeping out of the scenery. Mr. Ainouz has a painterly way with composition, and the toned-down performances work because the shots — one of Hermila muttering into a pay phone as a rusting water tower and the blue sky loom in the background comes to mind, as does a shot of a streamer clinging, in close-up, to an electrical wire — are so rich with emotion.

Without learning a single concrete thing about it, the viewer gets an intimate sense of Iguatu. Hard work is done in the heat, but so is lots of sitting around. The general feeling is one of inertia occasionally punctured by lust or a squawk of danceable music. Roads are bumpy and houses are not pretty; a new refrigerator, which doubles as an air conditioner, is considered a luxury item.

Hermila, who is unsentimentally played, with a trashy blond dyejob, by Ms. Guedes, looks much older than her 21 years, and she knows it. She deserves a chance to start over, and while Mr. Ainouz could have injected the question of whether she will get it with more urgency, he chooses to let that suspense unfold at a pace more appropriate to the remote, sweltering setting. The story offers no real surprises, but its slow arc is so even, and its quiet scenes, like Hermila, full of so much casual beauty, that such concerns soon evaporate.

Through August 28 (209 W. Houston St., between Sixth Avenue and Varick Street, 212-727-8110). The film’s screenwriter, Mauricio Zacharias, will sit for a question and answer session at Friday’s 8:10 p.m. show.