Option 4:
Play up the secrets.
[] It's about being a magical girl.
[] A magical girl is all about secrets. Secrets that are kept from others, and secrets kept from you. Kyuubey is a master at playing with secrets, but there are some you need to know before you even consider thinking about making a wish.
[] One of the first is this — a Soul Gem. It's where your magic resides; but more than that, it's where you reside — your self, your soul. This is, quite literally, the soul of a magical girl. This is me.
[] Your body can be torn to shreds — and you will feel every bit of that — but you can still keep functioning as long as your Soul Gem is safe, because that's where you are now. Sort of. In a metaphorical, true self sense, I guess. I mean, your body is still you, and you're still human, but the Soul Gem is also you. Well, it's tough to deal with, and it can be tough to deal with others once you realize this.
[] And it's not like that's the only secret you have to deal with. There are many things he won't tell you about being a magical girl, and many things you may not even realize you've lost until you look around and they aren't there anymore. The people you care about, and the people who care about you... Don't think that a wish will necessarily make things better.