Just Listen could have very well ended with the moment after Will's trial when Annabel meets Owen outside and kisses him. After all, isn't her secret finally out and resolved? Hasn't she made it and proved herself to be strong enough to stand up against Will Cash and what he did to her? But instead Sarah Dessen makes the choice to end the novel with a chapter at the radio station, where Annabel is now covering for Owen while he's grounded. She isn't even just playing his music; she's put together her own show with songs that she's chosen:
That had been four weeks ago, and while I was still nervous, I was also having fun. So much that Rolly was already bugging me to take the community radio prep course and apply for my own time slot, but I wasn't quite ready for that yet. But never say never. (20.10)
The ending shows how life has settled after all of the turmoil and grief. Annabel's testified against Will, but that's not where her story ends—which reminds us as readers that Annabel (like all victims of sexual assault) is so much more than the bad thing that's happened to her.
When we say goodbye to Annabel, her life is improving and she's becoming more confident in herself and shaping her reality into what she wants it to be. She has a good relationship with Owen and is mending things with Clarke. Even things at home are better than they were before. The story should not end on Will—it has to end on Annabel to show the readers how strong she is, and that's she's made it out of the storm.