(1) As a result of an alienation carried out under section 929, the acquirer becomes the owner even if the thing does not belong to the alienor, unless the acquirer is not in good faith at the time when under these provisions they would acquire ownership. In the case governed by section 929 sentence 2 however, this applies only if the acquirer had obtained possession from the alienor.
(2) The acquirer is not in good faith if the acquirer is aware, or is unaware as a result of gross negligence, that the thing does not belong to the alienor.