The timing of her beating from Khondamir was fortuitous—as much as a thing like that can be—because it happened right before Ramadan, so Jahanara is able to retreat to her rooms in the Red Fort to heal.
Jahanara goes back to work on the mausoleum, cautious but invigorated. Aurangzeb has spies there, so she's careful not to reveal her love for Isa.
The construction is costing Hindustan a fortune. Like, loads and loads of money.
Part of the reason the building is so costly is that it's being made from white marble. White marble doesn't grow on trees, after all.
Isa, Jahanara, and a few of the trusted artisans in their employ go to Delhi to get the marble to load it onto a barge and take it back to the site.
While in Delhi, Isa and Jahanara delight in subtly flirting, because they're basically anonymous there.
Nizam likes it in Delhi, too (he's been Jahanara's slave since her mother's death)—he likes finally being able to hang out with the dudes.
Seeing his happiness, Jahanara offers Nizam his freedom, but he turns it down. He believes his place is at her side.
On the way back up the river to Hindustan, Isa confesses he loves Jahanara so much that if it weren't for the mausoleum, he'd give anything to live in Delhi with her, with only their love to sustain them.
Jahanara feels the same way: duty calls, but if they didn't have those obligations, she'd give anything to be with him, too.
Isa designed the mausoleum with Jahanara in mind—that's how much he loves her.
Isa and Jahanara share their first real kiss and then pull away because they know an actual affair (you know, like one not totally conducted in their heads) could lead to their doom.