Hello @Walee0,
Giving a refund to a guest doe not guarantee a good review. They can still leave a bad review.
They cannot see your review until after they leave a review for you. So they cannot leave a bad review just because they read a bad one from you.
Airbnb works on trust and reviews. Please leave an honest review for this guest. Otherwise they can keep doing the same thing to other hosts. Maybe their last host didn't leave them an honest review because he or she didn't want to. That could be why you now have to deal with this guest.
If you don't leave a review and the guest does, their review will appear on your profile and listing page 14 days after checkout.
Please leave an honest review so as other hosts can know what your experience was with them.
Steve.