In the first game, Noble Rose's arrival is foreshadowed in not just Evil Rose's epilogue, but also in Anesthesia's epilogue as well. Unlike most of the other fighters, her eventual change is depicted as less of a "turn" and more a continuation of Fujiko Hinomoto story-arc.
When Evil Rose has won the tournament at the end of her storyline, she discards her mask- a symbolic gesture showing that she is no longer under the control of the Corperation. When Anesthesia wins the tournament in her storyline, the twisted woman's victory is quickly cut short when a mysterious voice (presumed to be Rose) leaves the nurse with a warning and a promice of retribution...

However, as the sequel is partially a reboot of the series, the Evil Rose persona is once again present. And the lack of real storylines in the game removes much of the complexity associated with the character in the original game. This time, Reiko is very much aware that the masked fighter is her sister. It's ultimately Reiko's intervention (instead of a conscious desision on Rose's part) that finally released Fujiko from the control of Anesthesia and 'the Corperation', and her eventual transformation...

After spending years as Anesthesia's puppet, the woman once known as Fujiko Hinomoto is finally able to break free from her control... Thanks in no small part to the arrival and intervention of her younger sister, Reiko, during the Roses Tournament. For various reason, Noble Rose is quick to dispute any connection to her former self (including her relationship to Reiko)- going so far as to say that she (as Evil Rose) had "killed" Fujiko Hinomoto. In truth, it's more likely that she has chosen to distance herself from Reiko in an effort to keep her out of danger- fearing that she might fall into the hands of her enemies.
This concern stems from the fact that Anesthesia more than likeely was/is targetting Reiko (observing her during her various matches) to use her a test subject. This threat to her younger sibling proved to be a strong enough motivation for Fujiko/Evil Rose that she was able to start resisting her conditioning (on multiple occasions)- intervening in matches to prevent the nurse from capturing her sister.

Realizing the extent of the danger involved, Noble Rose seems to have resigned herself to the possibility of dieing for her cause (ie. taking down Dr. Cutter and her corporate masters at all cost). However, she is not willing to risk her sister's life to achieve theis. And so she remains adamant that Reiko return to Japan in order to carry on the teachings and traditions passed down to the two of them by their mother, the late Kamikaze Rose. However, by the second game, she seems to have come to terms with Reiko's decision to remain in America and continue fighting in the Rumble Roses tournament. Later on, she even forms a Tag-Team with her called "The Kamikaze Typhoon" to compete for the Champions' Title in newly formed Tag-Team Division.

Regardless of her origins, Noble Rose emerges as a force for justice- not unlike a "Super Hero". She is intent on bringing down both Dr. Cutter and the Organization that wronged her and so many others. Because of this, her strong moral alignments leads her to attempt to enlist the help Yasha- another former victim and pawn of of their mutual enemies. Her morality is reflected in her personality as well. In her interview, she says her favorite words are "Justice. Love. And divine retribution." Rose also makes numerous references to Cutter, even citing her as the person that she'd "most like to meet" and declaring she will "pursue her to the ends of the Earth."