When it was dusk, Arabella finally learned of Renard's sacrifice to stay back inside the witch's forest for good, an act of self sacrifice for their salvation. While she knew Cassius who had heard the news felt the pinch in his heart, he had pretended as though it hadn't bothered him, as though he expected this from Renard as he is a loyal retainer.
But Arabella knew better than anyone else that a part of Cassius wasn't going to accept losing his closest aide for his own sake in silence.
And she was also guilty for being the cause for of it.
"Perhaps," she whispered to him at night while he brushed her wet hair in silence, his expression on the reflection of the mirror was full of a silent contemplation. "Perhaps it would be a better idea not to break the curse? As Lastor had told me before... it's not going to hurt me by living with the curse."
But Cassius knew she didn't know the entire story well.