It’s hard not to let your guard down when Dina Buno is around. In Dan Sickles and Antonio Santini’s film “Dina,” you’re first introduced to the agreeably brash 49-year-old as she sits for dental work, asking for an assistant to hold her hand for comfort during her appointment and in short order finding out all about her personal life, quickly learning the name of her daughter Gianna. As is learned during a later date at a nail salon, Dina has some level of Aspergers, along with “a little bit of everything,” according to her mother, which explains her aggressive inquisitiveness, but behind her confrontational demeanor, there’s a great warmth, so it comes with some sadness when she laments about her love life, “I’ll get by having crushes on people.”

This doesn’t remains true for long in “Dina,” just one of the many surprises in store for audiences in the second film from the directors who previously made “Mala Mala” about the transgender community in Puerto Rico, and while Sickles and Santini took a panoramic approach in capturing an array of characters in their debut, their narrow focus in their follow-up leads to a most poignant crowdpleaser. Unfolding with the simplicity of a great comic strip, the duo chooses a boxy frame and a largely static camera position with medium and far shots to chronicle Dina’s daily life, which takes a turn for the better when she meets Scott Levin, a humble Wal-Mart greeter with similar mental disabilities and a gentle spirit, and the two become engaged.

While the two may not look like a couple we’ve seen before on screen because of their neurological makeup, Dina and Scott look a lot more like a real couple than we’re used to seeing even in other documentaries, unable to be anything but emotionally direct with each other and wearing their heart on their sleeves as they go through the rites of passage for any pair headed to the altar, with one big exception. Although Dina, who was previously married, is eager for the honeymoon, Scott is far less so, eager to avert his eyes back to an article on his phone about the 50 Greatest Guitarists when Dina enters the room in her bra, and incredibly uncomfortable in conversations about sex. (When Dina hands him a copy of “The Joy of Sex” as a subtle suggestion during a day out at the beach, his first reaction is to be impressed at the 12 million copies of it that have been sold.)

The subject of sex may become the driving force for the tension in “Dina,” and certainly at the forefront of Dina’s mind, but it is a Trojan horse for Sickles and Santini to take an honest look at a middle-aged romance where passion becomes equally as important as compromise and the wounds of past relationships are always present despite a new partner. The film is brilliantly structured to give hints of past upset in Dina’s life that make her struggle to find someone who will treat her right extraordinary resonance, but by largely staying in the moment, there’s a natural rhythm that develops that makes it incredibly intimate regardless of how artfully it’s presented, allowing the audience to see themselves in the central characters.

There’s naturally fireworks as the big day approaches, and it would be unforgivable to spoil any of it here, but what’s truly impressive is how organically Sickles and Santini lay the foundation for an exuberant finale with such subtle stylistic touches throughout. Perfectly paced by editor Sofia Subercaseaux, the clever placement of pop songs and canny composition by cinematographer Adam Uhl frame Dina and Scott’s romance just right, resisting the suggestion of a grand romance, but full of feeling and quiet observations of the thoughtful consideration of the other that is far lovelier to behold than any big gesture could be. In telling their story in such a beautiful way, Sickles and Santini seem to realize how precious what Dina and Scott have before they do, but then again, it’s hard not to fall for Dina, or her film.

“Dina” does not yet have U.S. distribution. It will play at the Sundance Film Festival four more times on January 21st at 9 am at the Temple Theatre in Park City, January 22nd at 12:30 pm at the Rose Wagner Performing Arts Center in Salt Lake City, January 25th at 4 pm at the Redstone Cinema in Park City and January 27th at 12:15 pm at the Library Center Theater in Park City.