What does Jeremiah 33:6 mean?

‘Call to me, and I will answer you, and will show you great and difficult things, which you don’t know.’

For Yahweh, the God of Israel, says concerning the houses of this city and concerning the houses of the kings of Judah, which are broken down to make a defense against the mounds and against the sword;

while men come to fight with the Chaldeans, and to fill them with the dead bodies of men, whom I have killed in my anger and in my wrath, and for all whose wickedness I have hidden my face from this city:

I will cause the captivity of Judah and the captivity of Israel to return, and will build them, as at the first.

I will cleanse them from all their iniquity by which they have sinned against me. I will pardon all their iniquities by which they have sinned against me and by which they have transgressed against me.

This city will be to me for a name of joy, for praise, and for glory, before all the nations of the earth, which will hear all the good that I do to them, and will fear and tremble for all the good and for all the peace that I provide to it.’”