Arabella was impressed.
Ferdinand may not have memories of the past, but Alwin was already taking action with the assumption that the current Ferdinand would also be like the one in the past who would not let her go of her even in death.
Alwin was indeed so loyal to his lord, probably too much. But he must also not want to waste their efforts for this second chance to have come to pass.
From what Arabella could figure from her dream about the past last time, Alwin and Ferdinand had to take risks and offer something of importance for greater chances of the revival ritual succeeding.
She didn't know if Ferdinand truly had to offer his heart in a literal sense or something else but it must have meant he gave up something of great value. Especially if it meant reducing his lifespan or even limiting him to his human form and never being able to fly as a dragon again.
'Right, I have to work hard too. They already sacrificed so much for this second chance at life.'