Nepgear giving her all to save Rom from CFW Trick.
Rom being more willing to help Nepgear.
In Re;Birth 2, while Ram shouts at Nepgear for finding the sword, Rom holds no ill will, and even pats Nepgear to make her feel better.
After all the work, sweat, blood and tears that went into saving all of the Goddesses, each Candidate gets a touching reunion with their sister, but none more so than our duo of main characters, Nepgear and Neptune, the former who collapses crying into her older sister's arms. Neptune compliments her little sister on how much she's grown, and tells her she that will never leave Nepgear again.
One of Uni's bonus voices has her outright confess her love for Nepgear. This is never approached in game, but it's nice to see her admit it on some level.
Even though she was gone for three whole years, not a single person left Vert's guild in 4 Goddesses Online.
An event in the game has Histoire and Nepgear worried that Neptune is actaully doing a lot of work since she would usually try to avoid it. Nepgear goes to see if Neptune is okay and she is. The reason that Neptune is working so hard is because she knows she isn't the best CPU big sister role model to Nepgear and thought if things didn't change, Nepgear would come to hate her. Nepgear states she could never hate Neptune, which Neptune knew, but the thought still scared her. Nepgear states that a diligent sister is nice, but that she likes her sister who thinks that playing with her is the most important duty of all. She then help Neptune with her work so that they can play together sooner.