Yo iría más lejos.
Un desconfiado hombre lobo y una princesa deben rastrear a un caballero antes que éste inicie una guerra.

I would go with:

A distrustful werewolf must team up with a human princess to stop a vengeful knight from starting a war between humans and fantasy creatures.

The backstory as to what the knight did in the past is useful for the story, but not necessary in the logline. It would be better to include why it is this werewolf and princess that can stop him, rather than giving the motivation. Given the stakes, backstory motivation isn't required as part of the hook.

It's good!

I also like the "distrustful" attribute. It leaves a nice space for a character arc.

One thing: why "knight?" Is he gallant? Is it a knightly thing to destroy a village? Why not call him "warrior?" Or "warlord?" Or "wizard?"

Also, the logline would be simpler if the w-guy just comes, not comes and comes again.

Attempt to tighten an otherwise good logline. Unsolicited use of "wizard" ensues:

"When a wizard burns his village, a distrustful werewolf teams with a rebellious human princess to stop him from starting a war between humans and fantasy creatures."