A verité documentary that mirrors the minor-key humor, the rough-hewn texture, the gentle conflicts and awkward grace of many quirky indie narrative features, Dina cozies up unobtrusively to its complex, strong-willed protagonist as she takes charge of her impending wedding and lays out her expectations for a relationship with no shortage of challenges. After capturing Puerto Rico's trans community in Mala Mala, nonfiction filmmakers Antonio Santini and Dan Sickles here take a sensitive snapshot of two ordinary people on the autism spectrum who are determined to carve out a meaningful future together.

The film takes its title from Dina Buno, a 48-year-old family friend of Sickles, who lost her first husband to cancer and survived a violent knife attack by an unhinged subsequent boyfriend, referred to with an affectless absence of drama as "the psycho." That grim experience has done nothing to inhibit Dina's desire for close connection. So when an unexpected romance develops with Scott Levin, a Walmart staffer she met at an outer Philadelphia social group for neurologically diverse adults, wedding bells are all but inevitable.

However, while the love is mutual, there are plenty of obstacles to their union. Fiercely independent Dina has lived alone for more than 20 years, sustained by a level of self-esteem many of us might envy. Her primary go-to sources for life lessons include Sex and the City, Keeping Up With the Kardashians and I Am Cait. Scott always has lived with his supportive parents, and his closest relationship appears to be with his phone. When he moves into Dina's apartment to test their compatibility before marriage, their differences become apparent. Scott is good at declaring his affections but less skilled at showing them, and while Dina makes it abundantly clear that she considers sex a vital part of the package, that prospect appears to terrify Scott. Even including a partner when he's dancing seems beyond his reach.

Still, Dina is nothing if not determined, and her stream of patient explanations interspersed with vocal campaigning for her spousal rights makes her a delightful protagonist that we can't help rooting for. One of the film's most touching scenes is a bus trip Dina and Scott take together to the New Jersey shore. Scott already is somewhat freaked by the journey, then soothed by his first sight of the ocean. But he's reluctant to go near it until Dina coaxes him to wade in the lapping waves. He's a romantic, given to crooning songs like "Before the Next Teardrop Falls," but when Dina presents him on the boardwalk with a copy of The Joy of Sex as a gift, the message clearly nudges him outside his comfort zone.

What makes this candid, unpatronizing movie so engaging is that the sexual conflict is never set up as a deal-breaker, rather as an issue the couple has to work through in their own, mostly roundabout way.

Santini and Sickles — aided by cinematographer Adam Uhl, obviously doing everything possible to give the subjects their space — observe the preparations for the butterfly-themed engagement party; Dina's raunchy bachelorette night, with a hunky "cop" stripper; Scott's more subdued stag party at a bowling alley; their formal-wear fittings; the ceremony and reception; and their honeymoon at a Poconos resort, complete with a hilariously kitschy giant cocktail-glass spa in the newlyweds' suite.

Throughout, they interact with friends and family, not so much seeking advice as talking through their needs and anxieties. The warmth and guidance of Scott's parents plays in sharp contrast to Dina's tetchy exchanges with her mother, in which the two of them appear to talk at cross-purposes without really hearing one another. There are also sweet scenes with their mutual friends from the group, Monica Ferrero and Frank Costanzo, whose successful marriage gives Dina and Scott a model to emulate.

The filmmakers avoid extraneous commentary, letting their unselfconscious subjects' humanity speak for itself. The only real evidence of directorial hands at work is the choice to play the 911 call from Dina's boyfriend/attacker many years earlier, with her own oddly calm, almost apologetic voice heard in the background. That jolt of violent history is a smart way to remind us of what Dina has overcome and make us even more invested in seeing her build a solid marriage with Scott. And while we don't witness his miraculous transformation into a sex machine, a spontaneous display of tactile bedroom affection at the end of the movie suggests that a gateway toward harmony has begun to open.

Venue: Sundance Film Festival (U.S. Documentaries)
Production companies: Dan & Antonio Productions, in association with Cinereach, Impact Pictures, Killer Films
Director-producers: Antonio Santini, Dan Sickles
Executive producers: Dan Levinson, Robert Fernandez, Christine Vachon, Stephanie Choate, Dan Cogan, Jenny Raskin
Director of photography: Adam Uhl
Music: Michael Cera
Editor: Sofia Subercaseaux
Sales: Submarine

101 minutes.