en_tn_condensed/gen/34/21.md

These men

"Jacob, his sons, and the people of Israel"

peace with us

Here "us" includes Hamor, his son and all the people they spoke with at the city gate. (See: rc://en/ta/man/jit/figs-exclusive)

let them live in the land and trade in it

"let them live and trade in the land"

for, really, the land is large enough for them

Shechem uses the word "really" to add emphasis to his statement. "because, certainly, the land is large enough for them" or "because, indeed, there is plenty of land for them"

take their daughters ... give them our daughters

This refers to marriages between the women of one group and the men of the other group. See how you translated similar phrases in Genesis 34:9.