Having survived the Perilous Bed, Lancelot survives the Sword Bridge, and then he has disenchanted the castle in which Guinevere is a captive. He comes in to receive her great greeting and gratitude. But she's as cold as ice.
Campbell reads Lancelot's ordeal in Chrétien's Knight of the Cart as a test of total commitment to the beloved, where even a momentary hesitation — the three steps before the cart — constitutes a failure of the devoted will that the goddess-figure of Guinevere immediately perceives and judges.
, Transformations of Myth Through Time, 1990thesis