Don Bluth's The Princess and the Dragon

This film is from the director of Thumbelina and The Secret of NIMH, it's based on Beauty and the Beast.

Summary
An enchantress disguised as a beggar arrives at a French castle and offers a cruel and selfish prince a rose in return for shelter. When he refuses, she reveals her identity. To punish the prince for his lack of compassion, the enchantress transforms him into a dragon and his servants into animals. She casts a spell on the rose and warns the prince that the curse will only be broken if he learns to love another, and earn their love in return, before the last petal falls on his 21st birthday.

Ten years later, in a nearby village, a beautiful, young, book-loving woman named Bella dreams of adventure and brushes off advances from Gastonia, a handsome, narcissistic and arrogant animal-catcher. On his way to a fair and lost in the forest, Belle's father Martin seeks refuge in the Beast's castle, but the Dragon imprisons him. When Maurice's horse returns without him, Belle ventures out in search for him, and finds him locked in the castle dungeon. The Beast agrees to let her take Maurice's place.

Bella befriends the castle's animal servants, who invite her to a spectacular dinner. When she wanders into the forbidden west wing and finds the rose, the Beast scares her into the woods. She is ambushed by a pack of wolves, but the Dragon rescues her with a roar and communicates with the wolves and is injured in the process. As Bella nurses his wounds, a friendship develops between them. Meanwhile, Martin returns to the village and fails to convince the townsfolk of Bella's predicament. Gastonia then bribes Monsieur D'Argh, the crazed warden of the town's insane asylum to have Maurice locked up if Bella refuses to marry Gastonia.

After sharing a romantic dance with the Dragon, Bella discovers her father's predicament using a magic mirror. The Dragon releases her to save Martin, giving her the mirror to remember him with. After taking Martin to the village, Bella reveals the Dragon in the mirror to the townsfolk, proving her father's sanity. Realizing that Bella loves the Dragon, a jealous Gastonia has her thrown into the basement with her father, but both escape luckily. He rallies the villagers to follow him to the castle to slay the Dragon before he destroys the whole village. Martin and Bella escape with Chippy Chickadee's assistance, and Bella rushes back to the castle.

During the battle, the dragon's animal servant clan fends off the villagers. Gastonia attacks the Dragon in his tower, who is too heartbroken from Bella's departure to fight back, but regains his spirit upon seeing Bella return. He defeats Gastonia and captures him, but spares his life before reuniting with Bella. However, Gastonia almost wounds the Dragon with a knife but loses his footing from the Dragon's thrashing, and is arrested by some owl guards.[a] The Dragon falls into her arms as the last petal falls. Bella tearfully professes her love to the dragon and the curse is undone, reviving the Dragon and restoring his kind heart with all his animal friends who meet some human servants. The kind-hearted Dragon and Bella host a ball for the kingdom, where they dance happily.