It can't be entirely an act. When she isn't scared, Dora's understanding and compassion are real.
It's not that her being "a kind and good person capable of compasion and understanding" is an act, it's that her being a "chill and understanding"--ie, a relaxed, in-control person is an act.
Also, goddamn. Every time Sven and Faye come up on this forum, everyone always remembers a bizarre retconned version of their relationship where Sven was the cruel manipulative asshole and Faye was the pitiable victim, when that's pretty much THE OPPOSITE of how it happened. Yeah, it sucked that Sven had sex with Gina, and yeah, he knew it was a bad idea when he did it, but Faye had pretty much set him up to fail. She pulled all the strings in that relationship, and in the end I'd say her hurt was entirely through her own machinations. Sven had in fact been a selfish inconsiderate asshole in the past, but that was done with before he got together with Faye (and in large part because he was already getting emotionally invested in Faye).
To recap:
1. SHE kept coming over to his house to hang out, often not exactly invited, and butting into his life.
2. SHE was the one who made the first move on him when they had both been drinking.
3. She then rebuffed the SEVERAL moves he made to make it into something closer to an official relationship--she told him she expected it to be a one-time thing and basically scoffed at the idea of it being anything more when he inquired about their future plans, she turned him down for dinner and a movie, etc.
4. She continued to see him, all the while ignoring signs and suggestions that he was falling for her, and insisting that not only did he mean nothing to her except a roll in the hay, but that she didn't even want to hang out with him in public/with her other friends, treating him as a dirty little secret.
5. All the same she demanded that though it was not gonna be a relationship, he should not sleep with anyone else.
Quite reasonably, he refused to promise never to do so, although obviously Faye was free to leave when that happened. So he slipped and did, and Faye left as promised, and though it was dumb of him to do so, I'd say Faye mostly brought it on herself through her utter denial of both her own feelings, and Sven's feelings, and refusing to actually admit that he might be more invested in her than she wanted to think. (Any inimations of that on his part would be cut off bfore he even prperly started with "don't be silly, we all know you're just a womanizing jerk, so shut up and let me use you like a good uncomplicated sex toy".) I'd say she shot herslef in the foot there, although it's more like she handed a loaded gun with the safety off and a hair trigger to a man trying to regain the use of his hands after a lengthy paralysis, told him to aim at the target to her right and nowhere else, and then complained that he shot her in the foot instead.
If the genders were reversed, I don't think anyone would be treating her like the victim.
So please let's get over the shock that Sven may be acting like a decent guy who posesses feelings.