What does Genesis 34:22 mean?

Hamor and Shechem have gathered all the men at the gate of the city. Their purpose is to convince everyone to be circumcised. This was the condition given by the sons of Jacob (Genesis 34:14–16), when Shechem appealed for their sister, Dinah, to become his wife (Genesis 34:8–12). But this condition is a lie (Genesis 34:13). Shechem had brutally raped Dinah, and her brothers are intent on revenge (Genesis 34:1–7).

Part of the appeal is for prosperity. Jacob has come to this land with his massive fortune (Genesis 30:43). The idea of opening up trade and marriage with such a family would have been a strong temptation. It's been noted that Jacob's family are currently "at peace" (Genesis 34:21). Most likely, word of Shechem's crime had spread. The chance to avoid reprisals was probably something used to strengthen the case.

Now Hamor and Shechem describe the hard part: the only way for this to happen is if every man in the city is circumcised as they are. This ritual involves removing the foreskin from the penis. When done soon after birth, it's significantly less traumatic. Needless to say, it's painful and temporarily debilitating for adult males. This is an era before modern pain management and antibiotics. Jacob's sons are counting on that.