Note to A Midsummer's Night Dream, 2.1.81: "forgeries of jealousy"
forgeries: i.e., fantastic lies. Titania has accused Oberon of loving Hippolyta; Oberon gets back at her by claiming that she loves Theseus. Oberon's "proof" of his claim is that only the fairy influence of Titania could have enabled Theseus to escape entanglements with so many beautiful and loving women. Here, Titania responds by saying that everything Theseus has just said is only the product of his jealous paranoia.