Quentin Tarantino responded sharply to questions about the portrayal of women in his films and disgraced director Roman Polanski at a press conference in Cannes for his new drama Once Upon a Time in … Hollywood.

The director, whose latest effort premiered to rave reviews at the Cannes film festival on Tuesday evening, was in no mood to discuss difficult topics, at one point snapping “I reject your hypothesis” at a journalist who asked why Margot Robbie had so few lines in the film.

Robbie plays Sharon Tate, the actor and wife of Polanski who was murdered by followers of Charles Manson, in the film which stars Leonardo DiCaprio and Brad Pitt as a washed-up actor and his stuntman navigating a changing late-60s Hollywood.

When asked by another journalist whether he had any hesitation over depicting tragic real-life figures such as Tate in his film, Tarantino responded with a single word: “No.” The director also refused to speak about the issue of violence against women in his film, suggesting that to do so would spoil it for viewers. “I can’t really address that,” he said.

Tarantino was slightly more forthcoming in discussing Polanski, declaring himself a fan of the Polish director’s films. “I’ve met him a couple of times. I’m a fan of Roman Polanski’s work, particularly Rosemary’s Baby. I like that a lot.” However, the director said that he had not spoken to Polanski before making his film.

When asked why there was such fascination around the Manson murders, Tarantino said that he felt it was because they were “unfathomable”. “The more you learn, the more concrete it gets; it doesn’t make it clearer, it makes it more obscure the more you know,” he said.

Unlike Tarantino, Robbie was more forthcoming in explaining why she had so few lines in the film. “I think the moments on screen show those wonderful sides of [Sharon Tate] could be adequately done without speaking,” she said.

Robbie added that she agreed to agree to the role because she “felt that I could honour the memory of Sharon Tate”. “Quentin said to me she’s the heartbeat of the story. I saw her as a ray of light,” she said.

Brad Pitt, meanwhile, described Once Upon a Time in … Hollywood as “a rage against innocence. When the tragic loss of Sharon and others happened, what scared many even so today; it was a sobering dark look at the dark side of human nature. That pivotal moment was a real loss of innocence, and that’s what the film addresses.”

Despite Tarantino’s terseness, the director was happy to discuss his recent marriage to actor Daniella Pick. “I’ve never done that before,” he said of the marriage. “Now I know why: I was waiting for the perfect girl.”

Once Upon a Time in … Hollywood has been received warmly by critics, and currently holds a score of 86 on review aggregation site Metacritic. “I just defy anyone with red blood in their veins not to be bounced around the auditorium at the moment-by-moment enjoyment that this movie delivers,” the Guardian’s Peter Bradshaw wrote in his five-star review of the film.