Moscow, Belgium

At any given moment in this Belgian romantic comedy, it's impossible to say how Matty (Barbara Sarafian), a stressed-out 41-year-old postal clerk, feels about Johnny (Jurgen Delnaet), the scraggly, impossibly sweet younger truck driver who won't leave her alone until she accepts his compliments. On that fateful afternoon, she backs into his truck - or his truck hits her car. After their shouting match, he tries to get together with her. She agrees, then it's the same thing every time they get near each other: Go away, Johnny; Johnny, come over here. The ambivalence is mutual for me. I wanted to keep watching. I wanted to leave. In between, I prayed for the piano-accordion soundtrack to silence itself for just one scene (it's like being trapped in a little French restaurant that refuses to close).

In Matty's defense (the music remains indefensible), her life is in transition. A few months ago, her husband, Werner (Johan Heldenbergh), came down with a midlife crisis, moved out, started dating someone else, and left the three kids (the eldest is 17) in the apartment with her. Despite his flirtatious attempts to stay in the picture, she wants him to sign the divorce papers even though she's convinced he'll come back. Johnny is just an instrument to pique Werner's envy.

But Johnny doesn't seem to mind Matty's blunt insults. He calls her his Mona Lisa. He drives her home, naked, after they spend their first night together. He shares with her his cheesy but cute obsession with things Italian. He charms her. He gets on her nerves. The whirlwind makes Matty giddy, and it stresses her out. Between her kids, her job (where an old customer also has a crush), and her marriage, she's got a lot going on.

Written by Jean-Claude Van Rijckeghem and Pat van Beirs, and directed by Christophe Van Rompaey, "Moscow, Belgium" belongs squarely in the "I don't need another man in my life" genre, in which the heroine demurs, submits, rebuffs, then succumbs again. The movie just can't decide whether it likes romance or disdains it (Johnny is not entirely the prince he appears to be), whether it wants to be dark or bright.

Matty's uncertainty is taxing, even though Sarafian's performance is full of such rich negative life. Her face is long; her blond hair frazzled - she has Julie Kavner's frown and Frances McDormand's foul temperament. But the movie is so busy throwing changeups at Sarafian that she never has the chance to settle into any range of emotion for long. The curiosity to know how this character grew into such an embittered, prematurely old soul dissipates. Before long, you don't care whether Matty gets her groove back. It's hard to believe she ever had it in the first place.

Wesley Morris can be reached at wmorris@globe.com. For more on movies, go to www.boston.com/ae/movienation.