"I feel like it won't read in print very nicely if I say that wasn't really her style," Ryder, 38, tells BlackBook magazine's December issue. "But she seems to be a completely different person now."
Ryder, who was the film's lead star and executive producer, says that she "never had any bad feelings about" Jolie, 34.
"I was hurt that people thought that," she says. "Everyone assumed I was really jealous because I thought this would be my vehicle. We said from the very beginning that the actress who played Lisa would probably win an Oscar, because it was the big, great, showy part. But I always related to Susanna…"
In fact, she says she "fought very hard" for Jolie to get the part of Lisa. (Ryder has also said that at the time they worked together, she actually felt bad for Jolie because she was still struggling to be taken seriously as an actress despite her "beautiful" looks.)
Her only regret?
"I never really felt like I got the chance to know her," Ryder says.