Observation 1 about the films of producer Judd Apatow: Probably no one else is making movies today that balance sweet sincerity with such ribald, gut-busting laughs.

Case in point: the moment in “The Five-Year Engagement” when slobbish chef Alex (Chris Pratt) sings to his gobsmacked bride Suzie (Alison Brie). Mind you, it’s not just any song he’s chosen; Alex is doing a full-on, eyes-closed cover of Caetano Veloso’s version of “Cucurrucucu Paloma,” a song best known for its connections to art-house faves like “Talk to Her” and “Happy Together.”

The thing is, Pratt isn’t lampooning the song. He sings it with such utter sincerity, and such obliviousness to the I-really-mean-this faces that Alex is pulling, that the whole rendition is rendered hilarious. It’s a moment that speaks volumes about the Apatow oeuvre: Characters are often funniest when they discard all pretense and speak directly from the heart.

People may still talk about Jason Segel’s frontal nudity in “Forgetting Sarah Marshall” — Segel reteams with that film’s co-writer and director Nicholas Stoller here — but it’s the emotional nakedness of the characters that makes these movies work.

Also read: Tribeca Opening Night: Raunchy Judd Apatow Cleans Up With 'Five-Year Engagement' [5]

Observation 2 about the films of producer Judd Apatow: They’re too damn long, but the journey is generally so worthwhile, it’s a flaw that audiences are generally willing to forgive, like the halitosis of a beloved aunt. “Bridesmaids,” “The 40-Year-Old Virgin,” “Knocked Up,” and especially “Funny People” are all terrific movies, but they could each stand to lose about 20 minutes.

So it goes with “The Five-Year Engagement,” which tracks the pitfalls and byways that Tom (Jason Segel) and Violet (Emily Blunt) encounter on the way to the altar. The results are delightful, but there are moments during the comedy where you feel like you’re experiencing their lives in real time.

In many ways, Tom and Violet are a typical rom-com couple, from their meet-cute at a costume party (he’s in a bunny outfit, she’s Princess Diana) to Tom’s elaborately choreographed proposal on the rooftop of the San Francisco restaurant where he works as a sous chef. But in the same way that Segel and Stoller took the high concept of “Forgetting Sarah Marshall” and ran with it to Eric Rohmer territory, “Engagement” dares to examine the decidedly un-Hollywood realities of relationships, careers and compromises.

Violet hopes to do her post-doctoral work in psychology at Berkeley so that she can stay in San Francisco, but she doesn’t get in. Instead, she gets accepted at the University of Michigan, so Tom walks away from his booming culinary career by the bay and winds up making really good bagel sandwiches in a snow-covered college town.

Like the recent, underrated “Going the Distance,” this is a movie that acknowledges that regular folks can’t just spend a fortune on airline tickets at the drop of a hat — sometimes, keeping a relationship alive means that one of the two people involved has to pack up and move to a city that isn’t where they want to be. And the resentment of that move begins to build up in Tom, to the point where he becomes a shaggy-bearded hunter who serves venison at every meal and brews his own mead. Canceled weddings, tense reconciliations and what-are-we-doing discussions follow.

“Engagement” features the sharp dialogue, oddball supporting characters (including Chris Parnell as a househusband whose ineptly knitted sweaters come out like a unique form of outsider art) and R-rated clever bawdiness we’ve come to expect from the Apatow label, and Segel and Blunt make for such a believable and charismatic screen couple that it’s hard not to root for them to work things out and finally get to say their vows — they manage to make this will-they-or-won’t-they plot really matter.

(And heaven only knows what Frank Oz, who loudly objected to Segel and Stoller's script for "The Muppets," will make of the wildly funny scene where Blunt and Brie entertain a young child by having a very adult conversation in Elmo and Cookie Monster voices.)

Hey, if Tom and Violet can make it through half a decade of occasional mistrust and life’s random curveballs, then fans of “The Five-Year Engagement” can endure several minutes of excess movie.