Hitch is strong proof as to why Will Smith hasn’t yet starred in a romantic comedy proper.

Smith’s instant, gliding charm might leave even the best female foil overmatched, let alone the bland Eva Mendes, with whom he’s pathetically paired off here. No sparks fly out to encourage real rooting for these two to end up together, other than that, well, it’s the rule.

But isn’t it another rule that the best chemistry in romantic comedies is reserved for the leading man and his object of affection? Where Hitch slavishly follows that first law, it breaks this one and it’s what makes the movie work.

Forget Smith and Mendes — you’ll be hoping for a hook-up between Smith and Kevin James for numerous comic endeavors in the future. James, star of CBS sitcom The King of Queens, conveys a vibe that’s as humorously clumsy as Chris Farley, but quieter, sweeter and less manic — in other words, more normal.

Despite slight over-reliance on stupid slapstick, James’ rapport with Smith is good enough to save the movie. Without them, and a sweet touch of insight into dating politics, the overlong Hitch might be unbearable, crumbling under the title character’s insincere greeting-card dialogue and misunderstandings of preposterous proportions.

“It’s not how many breaths you take, but how many moments take your breath away.” What sounds like an FTD or Kay Jewelers slogan is instead one of the many mantras of Alex “Hitch” Hitchens (Smith). A New York “date doctor” who works only by referral, Hitch guarantees good-hearted guys a three-date inroad with the women whose knockout looks might seem intimidating.

Hitch’s focal client in the movie is Albert Brennaman (James), a schlep CPA in love from afar with Allegra Cole (Amber Valletta), whose wealth by inheritance he manages with his co-workers. Hitch — and the audience — is immediately endeared to Albert’s dogged determination, even if he will turn out to be the toughest customer yet.

But Allegra is not without her tabloid paparazzi, embodied here by gossip columnist Sara (Mendes). As she sneaks around to find out what the deal is with Albert and Allegra, the closed-off writer finds herself opening up to Hitch until perfunctory miscommunications complicate matters.

Director Andy Tennant knows his way around amiable but aimless romantic comedies (Sweet Home Alabama), and he keeps pacing brisk for the first 90 minutes. (It helps that the annoying Michael Rapaport, as a married friend of Hitch, thankfully disappears to make way for James.)

Disastrous dates, dashed best intentions, the appeal of a good date story and the nervousness of the male approach all are interwoven into the comic setups. And it ultimately understands that it’s not tricks and statistics that make love blossom; it’s heartfelt everyday gestures and actions.

The final reel tries to draw goofing laughs from the often-mocked ending of Jerry Maguire, whose conclusion Hitch could only wish to emulate for efficiency and emotion. Corny sax music, comparisons of Hitch to the devil and his painfully bad confession through a fisheye lens are just part of the most torturously extended ending to a romantic comedy since Something’s Gotta Give.

Still, there are far worse inconsequential romantic comedies than Hitch that you could be stuck renting on Valentine’s Day. It’s funny, witty, charming in its tale of one credible romancing, and that’s one more than most such movies see fit to give.