#They said to them

"Jacob's sons said to Shechem and Hamor"

#We cannot do this thing, to give our sister

"We cannot agree to give Dinah in marriage"

#for that would be a disgrace to us

"for that would cause us shame." Here "us" refers to Jacob's sons and all the people of Israel. (See: [[:en:ta:vol2:translate:figs_exclusive]])

#give our daughters to you ...  take your daughters to ourselves

This means they will allow a person from Jacob's family to marry a person who lives in Hamor's land.