A man wants to come for 1 night. I know nothing about him except his picture??

[Christine415]

How do I learn about my potential guest?

[Gerry-And-Rashid0]

@Christine415

If he has no reviews then ask him as many quotas you wish.

if you are not comfortable hosting him then decline the booking request 

[Linda108]

@Christine415  Many hosts are good at using technology to find out more about the guest using facial recognition and social media to find out more about the potential guest.  As @Gerry-And-Rashid0 have suggested, you can go back to the traveler and request they complete verification share why they are traveling.  I recently booked a reservation and was prompted to give the host information about my travel plans which I was happy to do.  Bottom line, you need to feel some sense of comfort with a potential guest to accept a reservation.  While not perfect, the Air BNB platform tries to facilitate that process.