It should not be so easy. Magic, in its simplest form, is nothing but emotion made will, and given form and purpose. There is more than enough emotion in his blackened old heart for this.
He lays out her body, broken and dirty from the grave; her hair matted with soil, on a table in his tower.
A pauper's burial at the edge of the forest was all the dignity they had afforded her; a lord's daughter, thrown unceremoniously in a hole to rot. She had been outcast even in death because of him.
It would have been wrong to leave her there, alone in the cold.
A twist of his hand, a bit of will, and her heart doesn't beat, her breast is still, but blue eyes open again.
Afterwards he clung to her like a child and sobbed apologies.
Using magic he dresses her in a fine brocade gown, and then guides her to sit while he carefully brushes the tangles out of her auburn curls. She doesn't even flinch when he tugs too roughly and pulls out a large hank of her hair.
Lastly he daubs a bit of the color the grave had stolen away on her lips and cheeks.
"There now," he coos, unable to resist stroking the side of her face, "How pretty you look."
He had read of… cases like this, where the revived did nothing but scream, or howl nonstop, or throw themselves murderously at anything living. There was a reason this particular kind of magic wasn't done. A reason it was forbidden. He wonders now if the character of the deceased mattered in their temperament after death.
When he guides her to rise, Belle runs her hands curiously down the front of the gown and along the swell of the skirts, feeling the material.
Her eyes are empty as they look at him, but he is nearly certain that she smiles.