@Cynthia-and-Stuart0 As others have said, this is almost certainly a scam of some sort. You say that you "feel quite good" about the guest. The fact is that scammers are the *best* at making people feel good about them; that's an essential part of their game.
Do *not* go outside the AirBnB system to accept payment, etc. In the first place, it's almost a certainty that you'll be ripped off in one way or another and you won't be under the protection of AirBnB. In the second place, it's a violation of AirBnB's terms of service for you to do so. When they find out, they'll delete your listing and ban you as a user.
As the others have also mentioned, don't cancel yourself. If the guest wants to cancel, have them do it. If you do it, the guest will get all their money back and *you* will be penalized and fined by AirBnB. If they cancel, all they'll lose will be the AirBnB service fee plus whatever they might owe you under your cancellation policy. Do *not* cancel the booking yourself.
I hope that you haven't already played into their hands...