What is the ruling on selling wigs to a hairdresser, and will the sin of selling them fall upon me if she sells them to someone who uses them for adornment and not out of necessity?

Connecting hair with impure hair or human hair is forbidden by the consensus of the four schools of thought, due to its deception, alteration of Allah's creation, and the impermissibility of benefiting from human hair. However, if the connection is made with something other than human hair and is pure, the schools of thought differ: The Hanafis permit it for women, using non-human hair to increase their hair. The Shafi'is forbid connecting hair for an unmarried woman unless with her husband's permission. The Malikis deem it permissible to wear a wig if it is placed on the head rather than being a connection. The Hanbalis consider it permissible out of necessity.

The preponderant opinion is the permissibility of selling wigs to married women.