“The Best of Me” opens Friday at Point, Eastgate and Star Cinemas. PG-13, 1:59, one star out of four.

I never thought a movie would make me long for the gritty realism of “The Notebook,” but “The Best of Me” certainly achieves that. It’s yet another adaptation of a Nicholas Sparks novel, which holds steady to a level of sugary mediocrity before taking a nosedive into the laughably bad in the final half hour.

As in “The Notebook,” “The Best of Me” also looks at the same couple at two different times of their lives. First, we meet Dawson (James Marsden) and Amanda (Michele Monaghan) in early middle age, reunited after having not seen each other for 20 years or so. Dawson is a hunky oil rig worker with a romantic streak, Amanda a dissatisfied trophy wife whose yuppie husband is an alcohol and golf addict. (It seems like the golf is really the problem.)

The pair return to their hometown for the funeral of Tuck (Gerald McRaney, in good-crotchety mode rather than bad-crotchety “House of Cards” mode). Tuck’s will includes an amazingly specific set of instructions designed to reunite Dawson and Amanda — it’ s almost as if he’s a desperate screenwriter trying to get his script moving or something.

Their wary present-day reunion is intercut with flashes back to the ’90s, when the air was thick with the Spin Doctors, and Dawson and Amanda were a couple of crazy teenagers who looked nothing like their adult selves. Liana Liberato might have plausibly aged into Monaghan, but Luke Bracey has at least six inches on Marsden Not to mention that he looks like he’s 26.

This is especially problematic, as young Dawson is supposed to be the abused scion of a backwoods gangster (Luke Bridgers) and his hillbilly crime family, who spend the ’90s sitting around waiting for crystal meth to be invented. Dawson is supposed to be horribly afraid of his Paw, despite the fact that Bracey could clearly crush Bridgers like a can of Dr. Pepper.

Anyway, Dawson flees his family and gets tucked under Tuck’s wing, who puts him to work tending to his garden. (Shirtless, naturally — “The Best of Me” knows who’s in the seats.). And then there’s a lot of melodramatic hooey as we learn how Dawson and Amanda fell in love and the convoluted reasons that Dawson ended the relationship and sent Amanda off to marry the golf pro.

That seems to be a running theme in Sparks’ works — men who dump good women with no explanation because, gosh darn it, they don’t deserve a gal like her. The women never seem to get much say in the matter, except to urge the men to forgive themselves for breaking their hearts. That’s mansplainin’ disguised as romantic self-sacrifice.

Here’s the thing — while the flashback stuff is pretty silly, Marsden and Monaghan as present-day Dawson and Amanda are charming enough actors to almost elevate the material in their scenes. Despite being saddled with dialogue like “How can you ask me to love you, when I’ve never even stopped,” they roll up their sleeves and try to make it work.

But then comes an absolutely, deliberately ridiculous third-act twist that tramples all that effort — “The Best of Me” doesn’t want to just tug at your heart, he wants to tie it to the back bumper of a monster truck and hit the gas. It’s a deeply cynical move that illustrates that, deep down, some love stories really don’t trust that a love story is enough to hold our interest. If detractors think Sparks’ movie adaptations are nothing more than big-screen soap operas, he doesn’t seem to disagree.