Legally, if it was given or gifted to you, he can't get it back: a gift, once given, cannot be ungifted and belongs to the recipient.Practically, if there is nothing in writing documenting that this was a gift and not a loan, if he's prepared to lie and take this to court, it will come down to who is more credible or believable, and/or has more credible or believable witnesses on their side; a court could potentially find for him and order you to return the trailer (or pay its value), if you have no proof this was gifted.