是真是假 Whether It Is Real or False
行者道：「既吃了便罷，只拿出人頭來，我看是真是假。」那小怪從門窟裡拋出那個頭來。豬八戒見了就哭道：「可憐啊！行者道：「既吃了便罢，只拿出人头来，我看是真是假。」那小怪从门窟里抛出那个头来。猪八戒见了就哭道：「可怜啊！
逐句解 Line by line
Pilgrim said, "If you have eaten him then so be it. Only bring out the head, and let me see whether it is real or false."
The reaction is pure Wukong: no grief yet, just verification. 便罷, then let it be, keeps 罷 at its full-toned reading as a verb of finishing, unlike the softening word he used at the gate a few passages back. 是真是假 puts the two possibilities side by side with no conjunction at all, which is the standard way of framing a straight test.
The little fiend pitched the head out through the hole in the gate.
門窟 is the hole in the door — the one Bajie punched with his rake, now serving as the fiends' only means of communication. Note that they still will not open the gate. The hole is doing everything: they look through it, they shout through it, and now they throw evidence through it.
Zhu Bajie saw it and burst out crying: "How pitiful!
可憐 is pitiful, and here it is an exclamation rather than a description — the sound of somebody's composure going. Bajie is the first to break, which fits the pattern of this chapter: he weeps early, weeps hardest, and does the practical work of burial afterwards.
Two reactions, side by side, and they tell you everything about the two characters. Wukong asks for the object so he can test it. Bajie sees the object and starts crying. Neither of them is wrong, and only one of them is useful.
The hole in the door is quietly becoming a character in its own right. Bajie made it in anger, and it has turned into the channel through which the fiends run their entire deception — every lie in this half of the chapter comes through a gap that the heroes themselves opened.