Minecraft wiki entry for Curing_a_zombie_villager, associated text: Curing a zombie villager grants you the Zombie Doctor achievement/advancement if it has not been obtained yet. If the cured villager has a profession, it permanently provides heavy discounts while trading to the player that cured them.‌[Java Edition only] There is also a heavy discount on Bedrock Edition with 1.16, another thing to keep in mind is that in Bedrock Edition, the discount spreads through the "talking" of villagers 16 blocks in a cube from the cured Villager.