If you’re crazy about ferrets, you’re enamored of them. It is less common but still acceptable to say “enamored with”; but if you say you are enamored by ferrets, you’re saying that ferrets are crazy about you.

If you’re crazy about ferrets, you’re enamored of them. It is less common but still acceptable to say “enamored with”; but if you say you are enamored by ferrets, you’re saying that ferrets are crazy about you.
