@Lizette22:
If your home is not set up as an instant book home then you have the opportunity of striking up a conversation with a prospective guest and deciding if you want to host them or not. However, with instant book, Airbnb's only criteria are that the guest has a confirmed telephone number, email address and payment information, all of which can be pretty much faked.
You can go into your Booking Settings and require additional things like government-issued ID and that they have other host recommendations.
If you are worried about false identities, then I would make the settings change to require ID. Just remember, the more criteria you set, the fewer bookings you will get.