The Five-Year Engagement (15)

The big ask: Emily Blunt and Jason Segel in 'The Five-Year Engagement' (Universal Pictures)

The most abused of all movie genres, romantic comedy nowadays gets a pass just by managing not to be contemptible. You have to blame the scripts in the main, but it's also curious how so many of its bankable stars fail the basic test of charm. Has anyone ever liked Gerard Butler in a romantic comedy? Film critics, who see these "romcoms" (ugh) week in, week out, have learnt to approach them with caution: the best you can hope for is some freshness in the playing, a few laughs, and a pinch of real feeling.

By cheering coincidence, and without making a big deal about it, The Five-Year Engagement has all three of those ingredients. True, it's hampered by a bland giveaway title, but then it does start at the point most romantic comedies conclude. We first meet San Francisco sous chef Tom (Jason Segel) and his girlfriend Violet (Emily Blunt), a doctoral student in social psychology, on their way to a party. He's behaving rather oddly, and under her persistent questioning in the car he cracks, presenting her with the engagement ring he planned to give her in a lovely spot overlooking the Bay. She says yes, but insists that they go through with his sweet romantic hoo-ha anyway, even though they both know how it ends: the film is a bit like this, too.

So their troth is plighted, and all set fair. As the countdown to matrimony begins, however, circumstances conspire to delay them. Violet's sister Suzie (Alison Brie) jumps the gun by getting hitched to Tom's co-chef and best friend Alex (Chris Pratt), and they have a baby to boot. Then Violet wins a two-year research fellowship, not at the local university but in Ann Arbor, Michigan. A decision must be made, and Tom agrees to move, sacrificing the big promotion he was due as chef at the Clam Bar. What's interesting is that the script (by director Nicholas Stoller, reuniting with Muppets co-writer Segel) presents the couple's dilemma very honestly. Violet explains that her own mother had to move for her husband's job, and resented him ever after. She's determined they won't repeat that mistake: she doesn't want Tom to be a martyr and do it just to please her. Tom isn't a martyr, but he does do it to please her – and he will eventually come to rue it. His disaffection is traced with a beadiness that's at once comic and deeply painful.

The film makes light of its two-hour length thanks to an exceptionally strong cast. The leads do outstanding work: Emily Blunt, who first came to notice as the brittle junior witch of The Devil Wears Prada, shows an entirely different side here, investing Violet with a warmth and humour that feel quite spontaneous. Jason Segel is Hollywood's favourite Mr Nice Guy at the moment, and you can see why. He projects just the right amount of decency as Tom, and, without becoming a wimp, shows how his accommodating nature subtly undermines him. The Five-Year Engagement sets its face against the old tropes of traditional romantic comedy and its foolish enshrinement of "perfection". It is altogether more humble, and more truthful, in charting the pitfalls of modern coupledom.