The premise is as old as The Taming of the Shrew—a sharp-tongued woman falls for a resourceful suitor who’s gotten past her defenses—but it works just fine in this buoyant vehicle for Sandra Bullock and Ryan Reynolds, whose chemistry is a happy surprise. She’s a high-powered New York editor and he’s her harried young assistant; when she faces deportation to her native Canada over an expired visa, he agrees to a sham marriage in exchange for a promotion. Director Anne Fletcher delivers more bite and brisker pacing than she did with 27 Dresses. PG-13, 104 min.