Responses
He's basically saying that marrying Cayena off to some noble is the only way he'll be able to control her now, since she's rebelliing and becoming really powerful.
Well, she is looking for 'freedom.' The only two ways to invisibly cage her is by letting everyone in the trade routes and the kingdom know how she looks. So, if she runs away, everyone will recognize her. The second method is to get her married to someone within the kingdom.
So what does he mean by marriage is the only option left and can someone tell me the spoilers