Comedy is supposed to be about more than silly accents and even sillier slapstick, isn't it?

So just try and explain exactly why a film like "The Whole Nine Yards," which largely relies on both of those old standbys to mine laughs — along with an all-too-familiar premise and script — manages to nearly succeed.

That's not to say this comedy is an all-out laugh riot. It starts much too slowly, and there are some unfortunate R-rated tendencies that seem excessive, in spite of the already dark material.

But, in that handful of scenes where the whole thing comes together, it is a lot of fun — and it's certainly better than the ads make it appear.

Of course, one big reason is the cast, which includes Matthew Perry and Bruce Willis.

Perry stars as Nicholas "Oz" Oseransky, a financially strapped dentist who's trapped in a loveless marriage with French-Canadian gold-digger Sophie (Rosanna Arquette, sporting one of the most ridiculous French accents since the Monty Python boys).

Oz is desperate to get out of the marriage, which is where his new neighbor, Jimmy Jones (Willis), comes in. Being only a "transplanted" Canadian, Oz immediately recognizes that Jimmy is none other than Jimmy "The Tulip" Tudeski, a Chicago hitman who's on the run after turning state's evidence on his former mob bosses.

So, the conniving Sophie pitches a scheme to Oz: If he'll inform Jimmy's ex-employer (Kevin Pollak, also sporting a goofy accent) about his whereabouts and then collect the "finder's fee," she'll give him a divorce.

Needless to say, things don't go as planned. First, Oz falls in love with Jimmy's estranged wife, Cynthia (Natasha Henstridge). Then he finds out that Jimmy may be in on the whole scheme with Sophie — or he could be playing all sides against each other.

This game of shifting alliances and different assassination schemes sounds like it could become confusing. But director Jonathan Lynn ("Trial and Error") keeps things moving along so quickly — in the second half, at least — that you probably won't care.

Besides, the stars seem to be having a ball, with Perry finally showing some of the goofy charm he regularly exhibits on TV's "Friends" and a very relaxed Willis barely restraining a smirk.

But as much fun as those two seem to be having, they're still nearly upstaged by supporting performers Amanda Peet (from TV's "Jack and Jill") and Michael Clarke Duncan (from "The Green Mile"), who steal a few scenes as Oz's would-be hitwoman receptionist and another mob enforcer, respectively.

"The Whole Nine Yards" is rated R for violence (mostly gunplay), profanity, female nudity, use of crude slang terms and some sexual humor, simulated sex and simulated drug use (nitrous oxide), done for laughs.