A few things hamstring the “Affair to Remember-ish” romance “The Last Letter from Your Lover,” a Netflix film adapted from the Jojo Moyes novel.

One is casting. Shailene Woodley and Felicity Jones are marvelous, as one would expect, with Woodley as a posh 1960s Londoner trapped in a loveless marriage and Jones as a modern day London reporter who stumbles across the letters that linked that ’60s woman to another man and a “passionate.”

It’s a bit of a stretch seeing Woodley (“Big Little Lies”) as a ’60s socialite. But Jones as a plucky, lovelorn reporter who must simply find out “how it came out?” That’s a no-brainer.

It’s the menfolk cast opposite these two magnetic stars who let down the side. They practically wilt in their presence.

And then there are the letters themselves. As emotionally repressed as the English stereotype is, you’d think the Land of Shakespeare could come up with something more spicy than the banal “We could be happy, so happy” bloodless “Brief Encounter” prose the mysterious “B” or “Boot” writes to court a married woman.

Those shortcomings combine to make “Last Letter” a bit of a hard sell.

Jones is Ellie, a features writer for a London newspaper not quite over her last break-up, given to drunken hook-ups and clever if somewhat soul-bearing stories on “passionate vs. ‘companionate’ love.” The death of a prominent former editor sends her to the archives to dig into that woman’s life. And once she gets past the pedantic pissant (Nabhaan Rizwan) who officiously safeguards those archives, she stumbles into letters from “B” to his beloved “J,” neither one of them being the editor Ellie is supposed to be researching for a definitive obituary.

Flashbacks take us back to the London of the ’60s, where married-well Jenny (Woodley) is recovering from a car accident that left her physically-scarred and with little memory of the life she led before it. Her domineering, aloof and often-absent husband (Joe Alwyn) isn’t much help. But eventually, she too stumbles into a letter from this “Boot” fellow, stashed inside a copy of Evelyn Waugh’s comic riff on journalists, “Scoop.”

“Boot” was the name of the hero of that book. And as Jenny starts her own digging into clues from these letters, she discovers it was a pet name she gave to a journalist (Jacob Fortune-Lloyd) who came to interview her globe-trotting husband.

So the movie is giving us two tame versions of “meet cute” — Jenny and “Boot,” getting off on the wrong foot, but with the writer eventually charming the suffocated society wife, stealing her heart and unleashing her passion, and the far “cuter” “meet cute” of Ellie getting over her foul-mouthed annoyance at this fellow Rory blocking access to all she wants to find out about “J” and “Boot.”

“Last Letter” takes us through the present day research and the ill-fated affair that preceded the accident that took away Jenny’s memory.

The mystery-solving part of this plays a bit like “Letters to Juliette,” for those who know their epistolary screen romances. Jones makes this half of the story sweet and fun, although she has to do most of the romantic heavy lifting, and every time she describes the letters as being “so rich in feeling” we have to wonder how repressed the pretty English reporter is herself.

Woodley has to look comfortable in upscale ’60s fashions — evening wear with diaphanous capes, a sailing dress that looks “Mad Men” secretarial, with even midriff-baring casual wear requiring gloves and those little pillbox hats of the era.

Wealthy Jenny is hardly the 20something product of Swinging London. But would she really be this conservative? Did no one notice how Jackie Kennedy dressed for a day of sailing? Capri pants, etc?

And Woodley’s Jenny has to suggest timid compliance with a dismissive, interrupting husband and a willingness to swoon over a reporter who doesn’t exactly swagger into her life. She does, but the romance seems a personality/charisma mismatch, something the film’s leaden pacing forces us to notice.

The leads make this tolerable. The ’60s pop soundtrack of Melanie, Nancy Sinatra and Lee Hazlewood duets and the like and scenes set on the Riviera seem borrowed from a sunnier movie than the sad-faced, charisma-imbalanced slog that “The Last Letter from Your Lover” is.

MPA Rating: TV-MA, sex, profanity

Cast: Felicity Jones, Shailene Woodley, Jacob Fortune-Lloyd, Joe Alwyn,
Nabhaan Rizwan and Ben Cross.

Credits: Directed by Augustine Frizzell, script by Nick Payne and Esta Spalding, based on a novel by Jojo Moyes. A Netflix release.

Running time: 1:50