Rolf was surprised to hear that apparently they'd been recommended for this that someone thought the two of them could help. He squeezed Luna's hand when Dumbledore reminded them of how she had helped Harry, yes he remembered those stories.
But the idea of stopping Death Eaters, of preventing attacks like the one that had taken their home, Luna's father? Rolf didn't know how he could say no to something like this. Not after all they'd lost, if they could prevent that from happening again, to another family? Didn't they owe it to themselves to try.
He glanced at Luna for a moment gauging her thoughts on Dumbledore's proposition and nodded. "Yes, yes I think we're interested." He was and he'd let Luna voice her own thoughts on it of course.