It's definitely the biggest part of the episode, because the narrator talks about the battle, and then he's like, "And then! Important point!" But it's not a confession. He talks about how Serena was wavering on the path as a Performer, but now she comes to a decision. And her decision is... He doesn't say, but based on that context, I'd say she's almost definitely going to continue on as a performer. Unless they're just baiting you there.
Bonny: (...Ok, so what she's saying here is kinda vague for me, an intermediate speaker. She says, "Zettai ni mitenai?" Ok, so, "Zettain ni" means "absolutely," or "defininitely." And then "mitenai..." I know "not trying." As in, "You're definitely not trying it?" Or, I think it could also mean "doesn't seem"... The general meaning could be that the choicei isn't what Bonnie expected from Serena? Or something. I'm actually not sure how vague this would be for a fluent speaker... it might be purposely vague, and won't be clear until there's context.