Cernunnos laughed; he didn't mean it cruelly or meanly, it was just... so far from what he'd expected that he didn't know what else to do.
He held up a hand to beg for a moment to pull himself together, and he could swear he heard his antlers rattling with the giggles he was holding in. "I'm sorry, I promise that I'm not laughing at you," he apologized immediately. "I should have realized you're not like every other woman that has to go through this. I'm just accustomed to explaining things a few times before it sinks in," he explained further. "It is no slight against you, and I offer you sincere apologies."
And then he started to actually consider what she'd asked, even as he stuck his head out the door, and hailed the first boy he saw. He requested several buckets of both hot and cool water, and a small tub, then closed the door and looked back at Rosmerta. "I see no reason to ask you to step aside," he said after another moment. "These are good people, and a doubly-bountiful harvest only benefit them all. Do what is in your heart, and I shall do the same, and the people will reap the rewards."