The words "be dismayed" mean that someone has caused them to be afraid and mean basically the same thing as "fear." This can be stated in active form. Alternate translation: "no one will make them afraid anymore" (See: [[rc://en/ta/man/jit/figs-doublet]] and [[rc://en/ta/man/jit/figs-activepassive]])
Yahweh speaks of himself by name to express the certainty of what he is declaring. See how you translated this in [Jeremiah 1:8](../01/08.md). Alternate translation: "this is what Yahweh has declared" or "this is what I, Yahweh, have declared" (See: [[rc://en/ta/man/jit/figs-123person]])