Is it necessary to throw a Splash Potion of Weakness to cure a zombie villager?

Solution 1:

As the Minecraft Wiki says:

Zombie villagers can be cured by using a golden apple (regular) on them while they are under the effects of Weakness, which can be applied by:

  • A splash potion of Weakness thrown by the player, a dispenser, or a witch.
  • An area effect cloud of Weakness from a lingering potion.
  • An area effect cloud of Weakness from a creeper explosion.‌
  • A tipped arrow.
  • A command (/effect @e[type=zombie_villager] weakness)

Thus, any source of the weakness effect will do, whether or not it comes from a potion.