@Anna10207 Welcome to the community, and hosting 😊
If this potential booking is through Airbnb, how did they come to contact you at your email address? Be wary with off platform communication. Payment is between guest and Airbnb, not host and guest. If they book, it should be through the platform only, and Airbnb will take their payment, not you. How they make that payment/who pays what is between the guest and Airbnb. All that matters is that you see a booking is 'confirmed' (meaning payment was successful) after it's made, and that you receive your payout from Airbnb 24 hrs after a guest checks in. Here is some info on payment methods you can share with this person,
https://www.airbnb.ca/help/article/126/what-payment-methods-does-airbnb-accept
On a side note, you might advise the guest to familiarize themselves with the terms and conditions of the platform and to contact Airbnb if they have any questions. You should do the same, as a new host. All your questions are answered in the help pages and the various policies. This forum is a valuable resource for you, and asking questions here is perfectly acceptable, but no replacement for thorough reading of policies etc.