"I have a mission of sorts. Not one imposed on me by others, but one of my own makings. I can no doubt accomplish it without your involvement or knowledge, but allies are always a valuable resource. I will not, however, allow myself to be betrayed. If you take the vow, I would design the wording in such a way that you will be released the moment my mission is completed. I have other allies I plan to bring into the fold, and I will ask them to make a vow as well. We can live perfectly well as guardian and ward, vampire and dhampir, mentor and mentee, without a vow, but you will be cut out from all business to do with my mission. If you want to hear more details, I will give them, but if you then choose to not make a vow, I will have to obliviate you. My secrets must be protected."