Negotiate with Sir Erhart, but get all the wrong answers. But don't get caught by any bandits, or they will attack you.
At night(recommended) sneak to the chest that Hans Capon's necklace in it, unlock it and take the necklace.
Sneak into the camp and disguise yourself as Alphonse Nuckelavee is a horse introduced in the The Amorous Adventures of Bold Sir Hans Capon DLC.
