Sealed with a kiss? How about a handshake instead? That’s how Lucy (Dakota Johnson) prefers to do business when it comes to matters of the heart, whether breaking up or making up. As a professional matchmaker, she approaches every potential connection as a deal to be made — people as balance sheets to be weighed, equations to be solved. If only the math were as simple as she believes it is.

Celine Song’s sophomore feature “Materialists” draws on the writer- director’s own experience as a matchmaker, so this romance about the art of the deal is grounded in details that could only come from witnessing the trade firsthand: the outsize expectations, specific requirements, small disappointments and big crises that come from trying to put one and one together.

Lucy is a bride whisperer and the keeper of her clients’ confidence. They don’t have to believe they’ll marry the loves of their lives because she believes it for them. She’s cool and impenetrable, ready with the right words, or a mysterious Mona Lisa smile. But what about her own love life? She flippantly declares that she’s only going to marry rich.

Enter Harry (Pedro Pascal), the brother-in-law of one of her clients, whom she encounters at their wedding. He’s a unicorn: wealthy, handsome, a full head of hair, and most importantly, tall. Lucy tries to recruit him for work, but he only has eyes for her.

Enter John (Chris Evans), a hunky waiter who delivers her preferred drink before she can order it. They’re too familiar, he’s too charming, and there are too many memories in his old car. He’s Lucy’s past and the source of her romantic hangups. Soon, a love triangle is afoot.

“Materialists” is a romance of the “they don’t make them like this anymore” ilk, with smart dialogue and relatable yet aspirational characters. It is also decidedly a film from the writer- director of “Past Lives,” another thoughtful film about a love triangle and the way our pasts haunt our futures. Once again, at the center, is a woman weighing one man against the other. The difference between Lucy and Nora of “Past Lives” is that Lucy, in her chosen profession, has let her head take the lead over her heart.

Working with the same creative team from “Past Lives,” Song has created another beautiful, richly rendered New York City for her characters to inhabit. The costume design by Katina Danabassis communicates much about our characters. Lucy’s fashion mimics her emotional journey from poised and put- together professional to a more relaxed and romantic version of herself, as her walls finally crumble.

The crack in her facade that reveals the shoddy construction of her belief system comes not from the men in her life, but from a crisis with a client. Lucy has overlooked that these are still people after all. Lists of superficial traits can’t account for quality of character.

Song’s script is note- perfect moment to moment, the dialogue delivered earnestly by the cast. But on a structural level, there are a few transitions where Song pushes the dramatic stakes, and the strain shows in a film that otherwise feels so real.

These narrative wobbles, coupled with a curious, somewhat silly choice for a bookend are the imperfections on the surface of “Materialists.” The power of Song’s ability to craft such an absorbing, transporting love story make these flaws easy to forgive. As Lucy discovers, love isn’t a problem that can be perfectly solved. Sometimes, it’s the wrong numbers that manage to add up.

MPA rating: R (for language and brief sexual material)

Running time: 1:56

How to watch: In theaters