Character Analysis
Romilda is the student who, according to Hermione, has been trying to sneak Harry a love potion for some time...and then later ends up slipping it to Ron by accident. Sometimes Cupid's arrows can get lost in the mail, guys.
So, yeah, Ron briefly thinks he's in love with Romilda, has to get an antidote from Slughorn, and then ends up poisoned while he, Harry, and Slughorn are celebrating Ron's recovery from the love potion. Oops.
So, er, she actually manages to cause a lot of trouble, even though we really don't see that much of her.