Passage
At that time, saith Jehovah, will I be the God of all the families of Israel, and they shall be my people.
At that time, saith Jehovah, will I be the God of all the families of Israel, and they shall be my people.
Jeremiah 31:1 At that time, saith Jehovah, will I be the God of all the families of Israel, and they shall be my people.
Jeremiah 31:2 Thus saith Jehovah: The people [that were] left of the sword have found grace in the wilderness, [even] Israel, when I go to give him rest.
Jeremiah 31:3 Jehovah hath appeared from afar unto me, [saying,] Yea, I have loved thee with an everlasting love; therefore with loving-kindness have I drawn thee.
The verse centers on "time", "saith", "jehovah", "families", "israel", "shall", and "people". It is saying that the verse draws attention to "time" and "saith", so its meaning should be read from those terms before moving to application.
The next verse adds "Thus saith Jehovah The people that were...", so "time" and "saith" should be read forward into that movement. In Jeremiah context, the local focus is covenant, worship, and faithfulness.
A plain takeaway is to answer the verse's own emphasis on "time" and "saith" with trust shaped by these words, not by a vague optimism outside the passage.