“Brooklyn” is a soft, cozy blanket of a movie, capable of producing content smiles at almost a weapons-grade level. Adapted by Nick Hornby from Colm Toibin’s novel, and directed by John Crowley (“Boy A”), this story of an Irish girl who emigrates to New York in 1951 is sweetly romantic but never sappy, just heartfelt and simple.

And funny! It’s also funny. I love this movie.

The Irish lass is Eilis (pronounced “Ay-lish,” more or less) Lacey, and she’s played by Saoirse (beats me) Ronan, who since “Atonement” has been staking her claim as one of the best actresses of her generation. At the outset, Eilis is a meek provincial girl who’s been sponsored by a kindly priest (Jim Broadbent) to come to America. In Brooklyn, Eilis takes a room in a boarding house with other young women, run by the stern but not humorless Mrs. Keogh (Julie Walters). (When a casual conversation about skin care leads to discussion of whether Jesus dealt with acne, Mrs. Keogh shuts it down: “Ladies, no more talk about our Lord’s complexion at dinner.”)

Eilis gets a job at a department store while taking bookkeeping classes at the local college. She’s homesick at first, and unaccustomed to Brooklyn’s hustle and bustle (at least she moved in before the hipsters did). She exchanges tender letters with her mother (Jane Brennan) and sister (Fiona Glascott) back in Ireland, and the priest soothes her with the assurance that homesickness, like most sicknesses, will leave her soon enough.

You know what might help, though? Love! And thus she meets Tony Fiorello (Emory Cohen), an adorably pocket-sized Italian-American boy who treats her with the sort of chaste gentlemanliness you’d expect from good Catholic kids in the 1950s. When he brings Eilis home to meet his (stereo-)typically boisterous family, she prepares ahead of time by practicing eating spaghetti with the girls at the boarding house. That’s after she and Tony have this conversation:

“Do you like Italian food”?

“Don’t know, I’ve never eaten it.”

“It’s the best food in the world.”

“Well, why would I not like it?”

These two!

While Eilis’s new life in America has its challenges, the movie is half-over before anything develops that could really be considered a “conflict.” (It stems from Eilis’s old life in Ireland. Can you ever truly leave your past behind?) When the trouble does emerge, it’s a doozy — not because it’s big and dramatic, but because it’s simple (and relatable), and because it holds the potential for outcomes both joyous and heartbreaking.

Telling a mostly trouble-free story is risky, as many meandering, pointless films have learned the hard way. When this low-drama approach works, as it does so nicely here, it’s because the characters and their situations are sufficiently compelling by themselves, without antagonists or crises. Eilis is hardly a unique creation among movie characters, but Ronan uses her ordinariness to her advantage, creating a sympathetic Everylass in whose happiness we find ourselves increasingly invested. Emory Cohen’s unassuming work as the kind boyfriend is also essential. Like Ronan, he creates a fully developed character out of the most basic raw materials.

Many feel-good films achieve their warm fuzziness by being phony. They oversimplify a suitor so he’s clearly the wrong choice; they contrive drama through implausible plot turns; they use whimsical quirks in place of character traits. “Brooklyn” does none of that, presenting instead everyday characters whose lives follow a familiar trajectory, yet who are compelling and vivid. It’s the authenticity that sells it. If you leave this film without a smile on your face, you must have done something wrong. Go back and watch it again.

A- (1 hr., 51 min.; PG-13, a little profanity, a scene of fairly discreet sexuality.)