真手段 No Tricks Only True Skill
羅剎道：「孫行者，你在那裡弄術哩？」行者道：「老孫一生不會弄術，都是些真手段，實本事，已在尊嫂尊腹之內耍子，已見其肺肝矣。我知你也饑渴了，我先送你個坐碗兒解渴。」罗刹道：「孙行者，你在那里弄术哩？」行者道：「老孙一生不会弄术，都是些真手段，实本事，已在尊嫂尊腹之内耍子，已见其肺肝矣。我知你也饥渴了，我先送你个坐碗儿解渴。」
逐句解 Line by line
The Rākṣasī said, 'Sun the Pilgrim, where are you working this conjuring of yours?'
那裡 is interrogative nǎ. 弄術 'to work a trick, to practise an art' — she assumes illusion, which is the natural assumption and the wrong one.
Pilgrim said, 'Old Sun has never in his life known how to work a conjuring trick. It is all true skill and solid ability. I am already taking my ease inside my honoured sister-in-law's honoured belly, and have had a good look at her lungs and liver.'
都 is again the adverb dōu. 尊嫂尊腹 doubles the honorific 尊 across sister-in-law and belly, which is grotesquely polite and exactly his manner. 耍子 takes the toneless suffix; 已見其肺肝矣 closes in a literary register with the particle 矣.
'I know you must be hungry and thirsty too. Let me first send you down a seat-bowl to quench your thirst.'
坐碗兒 is a nonce compound — a bowl to sit on — and 兒 is a true retroflex suffix. The mock-hospitality is the passage's device: he offers refreshment while preparing to kick her in the stomach.
老孫一生不會弄術，都是些真手段，實本事 — old Sun has never known how to work a trick, it is all true skill and solid ability. He says this having just turned himself into a gnat and hidden in a bowl of tea, and the claim is nevertheless defensible on his own terms: transformation is a discipline, acquired under Subhūti over years, and not conjuring.
The register of the boast is the pleasure of it. 尊嫂尊腹 — honoured sister-in-law's honoured belly — doubles the honorific across the person and the organ, and 已見其肺肝矣 closes in literary Chinese with the particle 矣, as though reporting an observation to a colleague. He is being grotesquely polite from inside her stomach.
The offer of a 坐碗兒, a seat-bowl, to quench her thirst is a nonce coinage and a threat. From here to the end of the block the assault will be conducted entirely in the vocabulary of hospitality, which is the chapter's most sustained joke and its least comfortable one.