Is “Voicemails” the least romantic word ever to appear in the title of a romantic comedy? It’s up there, surely. But consider it a suitable warning, since “Voicemails for Isabelle” isn’t terribly romantic either, though it puts much bright-eyed effort into proving otherwise. Writer-director Leah McKendrick‘s film challenges itself early, bringing its attractively matched leads together with a meet that couldn’t be less cute. Grieving the death of her sister, a young woman continues to leave the dead woman confessional voicemails as a coping strategy, all the while unaware that her sister’s number has been reassigned to a stranger in another city; upon listening to them, he falls swiftly in love.

Like “Sleepless in Seattle” with considerably more boundary violations, it’s a pretty creepy starting point for a tale intended to end on a blissful, wistful sigh. For all its otherwise precision-engineered sweetness, “Voicemails for Isabelle” doesn’t find its way there. Which is a shame, because Zoey Deutch and Nick Robinson — two reliably likable actors, alike in age, genre credentials and button-cuteness — do everything in their power to make you believe: By the time their characters, after the requisite period of third-act separation, finally let bygones be bygones and kiss, you really want to be happy for them. But you can’t quite forget that unnerving business with the voicemails.

Should you ever get distracted by such off-key turns, however, the film is quick to directly remind you which other movies it’s supposed to remind you of. When Wes (Robinson) first tells his best friends (Harry Shum Jr. and McKendrick herself) about the phone-stalking, they pointedly tell him: “Tom Hanks is America’s sweetheart, and you are not Tom Hanks.” (Could even Hanks have got away with it? Debatable.) Not long afterwards, a lovestruck Jill (Deutch) says aloud that she feels like Meg Ryan. And near the beginning, as her plucky younger sister Isabelle (Ciara Bravo) faces a hopeless cancer diagnosis, she smilingly says, “This is not ‘A Walk to Remember.'” And it’s not, though “Voicemails for Isabelle” does ambitiously work some terminal-disease weepie tropes into its sprightlier romcom formula.

The devoted relationship between the sisters is, in fact, the most credible and affecting element of McKendrick’s script, lending proceedings some earnest emotional weight even after Isabelle departs the scene early on — leaving Deutch to maintain that connection singlehandedly, via Jill’s frequent, lengthily conversational and sadly one-sided messages, a tricky device that the actress makes seem amiably natural. Jill certainly has a lot to talk about: A culinary school graduate currently working as a downtrodden commis chef to an abusive and egotistical restaurateur (Nick Offerman, sporting a deliberate faux-French accent) in San Francisco, she also has a run of bad dating experiences with, among others, her smarmy colleague Arthur (Lukas Gage) and dishy podcaster Tyler (Toby Sandeman). Career, love life and ego all on the fritz, then: If only someone could hear her vent.

Except someone can. Similarly lovelorn Austin realtor Wes at first listens to her redirected messages as an amusing curiosity, before he finds himself getting invested in her plight. Soon enough, he’s looking her up on Instagram and booking a flight to San Francisco so he can engineer an artificially spontaneous encounter. It succeeds in charming her, if not us. Robinson (“Love, Simon”) has a winning puppy-dog quality that he switches on to the max here, but that doesn’t temper Wes’ outlandishly controlling behavior — if anything, it just makes it seem more deranged.

You certainly buy the wounded fallout when, as she predictably must, Jill happens upon the truth behind her apparent stroke of romantic luck. (Where would this genre be in the 21st century without the telltale phone ping?) The idea that there’s any coming back from that is a far harder sell. And yet, this star pairing sparks enough to make you wish things had been different. Deutch, who headed up one of the first truly viral Netflix romcoms in 2018’s “Set It Up,” has enough straight-talking sincerity as a performer to counter the quirky affectations Jill has been loaded with; Robinson matches her twinkly-but-right-side-of-irksome energy beat for beat.

McKendrick, for her part, directs with smooth, perky proficiency, even if the film’s over-frequent, over-obvious needle drops — Taylor Swift’s “Marjorie,” with its “what died didn’t stay dead” refrain, is applied to awfully on-the-nose effect, though it’s more welcome than Benson Boone’s played-out “Beautiful Things” — contribute nothing but a certain algorithmic quality to the package. Still, no film in which characters get down repeatedly, vigorously and endearingly badly to Robyn’s “Dancing On My Own” is without its moments of truth.