Jules goes through a lot with Rue this season. After learning of Rue's concerning substance use from Elliot in episode four, Jules makes the decision to tell Rue's mother, Leslie. Jules's love for Rue shows in this moment because even though she knows taking that action will be unforgivable in Rue's eyes, she tells Leslie anyway because she can't bear the thought of something bad happening to her.
After giving Rue space, Jules finally approaches her at the end of the finale and expresses her love for her once more. Whether it's because she still can't forgive Jules for telling her mother about her substance use, that she senses Jules hooked up with Elliott, or that she just knows a relationship isn't good for her sobriety at the moment, Rue is still unable to rekindle her friendship with Jules. Rue wordlessly kisses Jules's forehead and walks away, and the last we see of Jules is her left in tears in the auditorium.
In her final monologue, Rue says she's not sure if Jules was her first love or not because she was high for too much of their relationship to know for sure, but she hopes Jules will forgive her for what she put her through.