en_tn_condensed/jer/32/44.md

write in sealed scrolls. They will assemble witnesses

The "sealed scrolls" are the deeds that a person would sign to purchase land. Other people would be witnesses to confirm the purchase.

reverse their captivity

"free them from their captivity." The abstract noun "captivity" can be translated as a verbal clause. See how you translated similar words in Jeremiah 29:14. Alternate translation: "free them from those who had captured them" (See: rc://en/ta/man/jit/figs-abstractnouns)

this is Yahweh's declaration

Yahweh speaks of himself by name to express the certainty of what he is declaring. See how you translated this in Jeremiah 1:8. Alternate translation: "this is what Yahweh has declared" or "this is what I, Yahweh, have declared" (See: rc://en/ta/man/jit/figs-123person)