Nobody goes to a romantic comedy looking for surprises. We go for

Nobody goes to a romantic comedy looking for surprises. We go for affirmation that, in the face of suspicious data, dubious reasoning, endless distractions, and daunting obstacles (real or imagined), fusion between two hesitant people can occur—even if it takes the G-force of the Large Hadron Collider to bring it about. The bristly main characters in John Patrick Shanley’s talky 2013 charmer seem a textbook illustration of Zeno’s paradox of Achilles and the tortoise, getting halfway closer, halfway closer, ad infinitum. There’s nothing the least bit edgy about Outside Mullingar, nor excessively sappy, so you can swoon at its abundant appeal and still keep your grumpus credentials in order.

In rural Ireland, the Muldoons and Reillys have owned adjacent farms since forever. Rosemary Muldoon (Emily Chisholm) has been nursing a grudge against Anthony Reilly (M.J. Sieber) for decades: At 13, he shoved her when she was 6, a comically trivial basis for her planned revenge. She owns a strip of land that blocks his family’s property from the road—compromising a possible sale. Early on we meet one surviving parent of each lovebird (Kimberly King and Sean G. Griffin, both terrific) and get an inkling of where the weird comes from. As the romantic pursuer, however bitter, Rosemary gets more to do than Anthony. Under cover of anomie, she seethes, stews, smokes, pines, coaxes, goads, accuses, and corners. Allure, as most of us have come to think of it, is not in Rosemary’s quiver; her desire squeezes itself into the refrain, “Girl needs a chat.”

Sieber, playing an evasive depressive, is stuck in defensive mode. His Anthony declines all bids except a credulity-stretching one from his dying father. Director Wilson Milam was probably wise to guard the “secret” of Anthony’s love, but this is accomplished with a lot of head-down, eyes averted chore-doing that often strands Chisholm on her own.

Still, the 90-minute one-act flies by, the excellent performances expedited by lyrical language (spoken in proficiently non-distracting accents) and jaunty passing humor. Doubt playwright Shanley, the screenwriter of Moonstruck, knows how to be funny when he wants to be. His smart, hearty/hardy characters have a full grasp of irony. Their miserable, sodden existence—sheltered by Eugene Lee’s flimsy-looking sets and alluded to by Geoff Korf’s painterly lighting—is the only life they can imagine. Conceiving of new things is a liability around here. As Rosemary laments, “Thinking’s worse than February.”

OUTSIDE MULLINGAR Seattle Repertory Theatre, 155 Mercer St. (Seattle Center), ­443-­2222. $17–$102. 7:30 p.m. Wed.–Sun. plus some Wed. & weekend matinees; see for schedule. Ends May 17.