Continuity mistake: After Belle says good morning to Jean Potts, when she feeds the apple to the donkey note the rope (crosstie) is tied off at the donkey's throat, but in the next closeup the rope is tied off directly to the halter knot at its cheek.
Continuity mistake: In the beginning of the movie for the song "Belle", her dress is tucked into her belt, exposing her under undergarments, for majority of the song. Then when she enters the library to exchange her book, her dress is down. (00:04:50 - 00:06:30)
Continuity mistake: When Belle goes to the castle to rescue her father, her father takes the horse back, but when Belle runs away the horse is still there.
Continuity mistake: When Belle finds her father locked up she's holding her stick with one hand, then the angle changes and she's using both. We switch back and she's using one hand again.
Continuity mistake: When Gaston and Le Fou approach the village on horseback, they watch Belle through a telescope. In the shot from behind, Le Fou has to stretch out to reach the telescope when Gaston passes it across and his fingers barely touch the end of it, but when the view changes to the front the horses are closer together and he is holding the telescope firmly in the middle.
Revealing mistake: When Belle exits her house, the reflection on the window by the door shows a rectangular flat roofed building, nothing to do with the old gable roof we see in further shoots. In the making-of we are revealed that the prop building is in fact rectangular and flat, with a green screen on top to allow for the CGI.
Continuity mistake: Gaston fires at the ceiling and debris falls all over, but in the next shots the debris is gone.
Continuity mistake: In the opening number, Belle picks up a loaf of bread at the start and puts it in a bag around her waist. Later in the number it's not there. There's a deleted scene which explains the disappearance, but with that scene missing, the bread just disappears for no reason, hence it's a mistake.
Other mistake: During the final fight, apparently Mrs. Potts can hold dozens of liters of boiling water inside herself.
Continuity mistake: When Le Fou enters the castle, he's holding a torch to his left - angle changes and it's suddenly to his right. The angle changes back, and it's back on the left again.
Continuity mistake: When Belle exits her house singing, in the front shot the building to the right in in shadow. The angle changes and it's suddenly much brighter.
Continuity mistake: After Belle gets the bread from the baker while she's singing, when she stops at the horse we see the halter rope looped twice around the horse's muzzle, but next shot it's wound around only once.
Continuity mistake: When the Gaston song is about to start, he says "Imagine Le Fou..." and Le Fou's arm swaps from resting on Gaston's chair to bent, between angles.
Continuity mistake: After Gaston ties Belle's father against the tree, the father's head changes positions between shots.
Continuity mistake: When Belle gets to the castle to save the beast she's wearing a coat. Where did she get it though? When she left the village she removed the top of her dress but did not have a coat in hand. (01:42:25 - 01:46:40)
Audio problem: When the wolves attack Maurice and Philippe, the wolves make growls that only big cats (lions/tigers) would make.
Continuity mistake: When we see Belle and her father talking for the first time, Belle's hair is behind her, hanging down her back. Then you see it resting on her shoulder. Throughout the entire scene, her hair changes between falling down her back or resting on her shoulder.
Continuity mistake: Right before Le Fou starts the Gaston song, the way Gaston holds the knife (when he says "A hunter...") changes between shots.
Revealing mistake: When the wolves attack the Beast, neither one leaves footprints on the snow.
Continuity mistake: When the Gaston song ends, Le Fou's hair swaps from messed up to brushed.
Answer: She didn't have to, the second Belle proclaimed her love for the Beast, the spell was broken. She would have seen her use her magic to reverse the curse. It would be obvious to everyone she was an enchanted being.