Yahweh speaks of himself by name to express the certainty of what he is declaring. See how you translated this in [Jeremiah 1:8](../01/07.md). AT: "this is what Yahweh has declared" or "this is what I, Yahweh, have declared" (See: [[rc://en/ta/man/translate/figs-123person]])
Here "hearts" represent courage. Also "the hearts ... will die" represents losing courage and being afraid. AT: "the king and his officials will stop being courageous" or "the king and his officials will be terrified" (See: [[rc://en/ta/man/translate/figs-metonymy]] and [[rc://en/ta/man/translate/figs-metaphor]])
Here enemies being ready to kill people is spoken of as if the sword was a person striking at people. AT: "our enemies are ready to slaughter us with their swords" (See: [[rc://en/ta/man/translate/figs-personification]])