乘善歸真 Riding Goodness Back to Truth
國王謝了恩。擺整朝鑾駕，送唐僧四眾出城西去。君臣們乘善歸真不題。国王谢了恩。摆整朝銮驾，送唐僧四众出城西去。君臣们乘善归真不题。
逐句解 Line by line
The king gave thanks for the favour.
Five characters, and note the direction of them. 謝恩 is what a subject does to a throne. The king is using it to a monk.
The full court equipage was drawn up, and the Tang Monk and his three companions were escorted west out of the city.
鑾駕 is the imperial carriage with its bells, brought out in full for the send-off. They arrived in a stolen chest under guard; they leave in a royal procession, and the distance between those two entrances is the chapter's first movement.
Ruler and ministers, riding on goodness, returned to the true; of them we say no more.
乘 is chéng, to ride or to avail oneself of — not the shèng that names a Buddhist vehicle, though with a kingdom converting on the page the echo is surely deliberate. 不題 is the storyteller's formula for dropping a thread: we will not speak of them again, and the book never does.
The kingdom exits on a phrase that sounds like doctrine and works like a curtain. Riding goodness, returning to the true — and then the narrator shuts the door on them mid-sentence and turns west.
It is worth registering how completely this arc closes. No loose thread, no promise to return, no cost to anyone travelling. The pilgrims converted a kingdom by accident and are gone before breakfast.