又是冤家 Enemies Once Again
行者聞言，大驚失色，心中暗想道：「又是冤家了。當年伏了紅孩兒，說是這廝養的。前在那解陽山破兒洞遇他叔子，尚且不肯與水，要作報仇之意；今又遇他父母，怎生借得這扇子耶？」行者闻言，大惊失色，心中暗想道：「又是冤家了。当年伏了红孩儿，说是这厮养的。前在那解阳山破儿洞遇他叔子，尚且不肯与水，要作报仇之意；今又遇他父母，怎生借得这扇子耶？」
逐句解 Line by line
When Pilgrim heard this he went pale with alarm, and thought privately, 'So it is an old enemy again.'
冤家 is an enemy, and in everyday speech very often one bound to you by a debt of grievance that will never be settled — the word carries a sense of being stuck with somebody. 心中暗想 marks private thought, which the source punctuates exactly as it punctuates speech aloud.
'The year I subdued the Red Boy, they said he was this creature's child.'
紅孩兒, the Red Boy, was the demon of chapters forty to forty-two, subdued by Pilgrim and taken into service by Guanyin as the Boy of Goodly Wealth. 當 is the dāng of time and place, "in that year." 這廝, "this creature," is contemptuous.
'Before this, at the Cave of the Broken Child on the Mountain of Dissolved Male, I met his uncle, who would not so much as give me water and meant to take revenge for the boy;'
解陽山破兒洞 belongs to chapter fifty-three, where the Immortal As-You-Will guarded the spring that undoes a pregnancy and refused it to Pilgrim on precisely this grievance. 解 is jiě; the 兒 of 破兒洞 is a full syllable meaning "child."
'and now I run into his father and mother. However am I to borrow this fan?'
借得 turns on possibility, so 得 is the light de — "how could it be borrowed at all?" The source runs this half together with the one before it; they are kept apart here because the sentence turns from statement into a rhetorical question, and the grievance climbs from an uncle to the parents themselves.
The woodcutter's last clause has landed. Pilgrim goes pale, and the novel gives him a paragraph of private thought in which he works out the family tree: the Rākṣasī is the Red Boy's mother, the Bull Demon King his father, and the Immortal As-You-Will of chapter fifty-three his uncle. What looked like a problem of geography has turned into a problem of kinship.
The precedent he reaches for is exact and thoroughly discouraging. At the Cave of the Broken Child the uncle would not give him so much as a bowl of water from the spring, on the grounds of what had been done to the boy — and an uncle is a remoter connection than a mother. Pilgrim is reasoning from a case he lost.
It is worth remembering what actually happened to the Red Boy. He was not killed; he was subdued and taken into Guanyin's service as an attendant, which by this novel's reckoning is a promotion. Nobody in this family sees it that way, and the chapter never once suggests they are wrong to feel the loss. The grievance driving the next three chapters is a mother's, and it is treated as real.