與他差不多 He Sized Up the Fiends Skill
八戒量著那妖精手段與他差不多，卻說：「我就死在他手內也罷，等我先走。」行者笑道：「這獃子先說晦氣話，怎麼得長進？」八戒量着那妖精手段与他差不多，却说：「我就死在他手内也罢，等我先走。」行者笑道：「这呆子先说晦气话，怎么得长进？」
逐句解 Line by line
Bajie sized up the fiend's skill as being about a match for his own, and said, "Well, if I die at his hands, so be it. Let me go first."
量 is liáng here — the act of gauging or weighing something up. The dictionary splits the character on exactly this line: capacity and magnanimity take the falling tone, while measuring and deliberating take the level one, and it cites a classical phrase for gauging a man's strength before acting. 著 is zhe. In 也罷, so be it, the second character 罷 is bà.
Pilgrim laughed. "The blockhead starts with unlucky talk. How is he ever to make progress?"
怎麼得 puts 得 at dé, the question-word family. 長進 is to improve, to get on — and 長 there is zhǎng, the growing reading, not the cháng of length.
He accepts, and he accepts with his eyes open. He has measured the fiend against himself, made it about even, and gone anyway — which is a different thing from the creature who walked off humming toward an imaginary lunch.
Pilgrim's response is to mock the tone of the acceptance. Not the risk, not the odds — the unluckiness of saying it out loud.