Whether the "Book of Comfort" ended with Jeremiah 33, the poetic oracles of chapters share its more positive outlook.
Chapter 32 opens while Jerusalem is under siege by the Babylonians. Jeremiah is in custody. Apparently King Zedekiah was not happy with the prophet's oracles against Judah, Jerusalem, and the king himself. While in prison Jeremiah learns that a field in Anathoth that is owned by his family has come available for purchase. As the next-of-kin he can redeem the field. And he does. This is a prophetic act/sermon rather like walking around Jerusalem wearing a yoke. It bears witness to YHWH's promise that Judah, after exile, Judah will be restored.
I will surely gather them from all the lands where I banish them in my furious anger and great wrath; I will bring them back to this place and let them live in safety. They will be my people, and I will be their God.
Jeremiah 33:1-16 is another oracle from the same time. Speaking through the prophet, YHWH decalres that the exiles will return to Judah and a good king from David's dynasty will rule over them. Verse 16 is a close parallel to Jeremiah 23:5-6. Only there the name "YHWH is our righteousness" was applied to the king. Here the name is given to Jerusalem.
Verses 17-18 promises that the Davidic kingship and the levitical priesthood will never end. The fact that this didn't quite pan out was no doubt a contributing factor in the rise of messianic expectation during the intertestamental period.
Verses 19-26 speak of YHWH's "covenant" with the sun and the moon. That covenant cannot be broken; neither can YHWH's covenant establishing Judah's kings and priests.
Chapter 34 returns us to the dark tone we've come to expect from Jeremiah. In verses 1-7 he predicts that Zedekiah will be taken into exile and die there but, if it's any comfort, he will receive an honorable burial. Thinking back to 2 Kings 25 you may recall that Zedekiah was indeed taken into exile, saw his sons killed, was blinded, and thrown into prison. It didn't go well for Zedekiah.
Verses 8-22 take the form of a narrative. During the siege of Jerusalem Zedekiah decrees that the citizens should free their Hebrew slaves. At first they comply. Then they renege. YHWH is displeased and gets a little sarcastic:
Therefore this is what the Lord says: You have not obeyed me; you have not proclaimed freedom to your own people. So I now proclaim ‘freedom’ for you, declares the Lord—‘freedom’ to fall by the sword, plague and famine. (Jeremiah 34:17)
Biblical quotes are from the New International Version. Next: Jeremiah 35-37