From the Super Mario Wiki
“Take it from me, Queen Rotunda! This is the best love potion I ever mixed!”
In The Super Mario Bros. Super Show! episode "Love 'Em and Leave 'Em" Hildy is employed by Queen Rotunda to create for her a love potion that would make the handsome Prince Pompadour fall in love with her. Setting to work, Hildy created the Passion Potion, a powerful love potion which could make it's drinker instantly fall in love with the first person they saw.
Later, after Queen Rotunda was informed by one of her Beezo minions that she had prisoners, Hildy gave Queen Rotunda some of her Passion Potion in a container, to be used in case Queen Rotunda ran into Prince Pompadour while going to see her recently captured prisoners.
Hildy was later seen at the wedding of Mario and Queen Rotunda, who, through an accident, had ingested some Passion Potion and become madly in love with Mario.
Eventually, after Queen Rotunda and Prince Pompadour, who had been among the attendees of the wedding, fell in love with one another after drinking some Passion Potion sneaked to them by Luigi, Hildy decided to make a toast to Queen Rotunda for not marrying Mario; unfortunately, Hildy, during her toast, drank some wedding punch that had a large amount of Passion Potion accidentally dropped in it by Luigi. Drinking this Passion Potion filled punch, Hildy instantly fell in love with the first person she saw after ingesting it, Luigi.
Having become obsessively in love with Luigi, Hildy began to chase him and the nearby Mario, Princess Toadstool and Toad all the way out of Rotunda Land.