Arabella had to say this though for Princess Seraphina not to cling to naive thoughts that she would help for free.
If there was something Arabella could do, she was willing to help as she, herself, had received a second chance at life. And she believed that as she had changed from her former ways, Crux could change as well.
However, Arabella was the Empress of Valeria. She needed to uphold Valeria's honor and the welfare of their people.
Crux had not only offended and insulted them with their actions but made a lot of their people suffer. Thus, Arabella needed a good reason to help or else her own people would hate her for helping their oppressors.
Arabella adored Seraphina's determination but she needed to consider what helping the latter would mean for Valeria.
Instead of getting further disheartened, a flicker of relief crossed Seraphina's features as she understood the underlying meaning of Arabella words.
[It wasn't a rejection!]