It's breakfast at the Boffins' place, and both Bella and Rokesmith are there as usual. Mr. Boffin usually loves these breakfasts, but on this occasion, he comes in with a dark face and you just know there's some trouble brewing. It's probably because he knows about Wegg's plan.
But that's not it at all. The reason Boffin is really angry is because the Lammles have told him about Rokesmith's declaration of love to Bella Wilfer. That's old news to us by now, but Boffin is hearing it for the first time. He thinks that Rokesmith is just a fortune hunter who wormed his way into Boffin's house with the hope of getting Bella's money.
Bella tries to defend Rokesmith, but Boffin won't hear of it.
The conversation blows up into a ten-page fight, with Boffin yelling at Rokesmith and Bella yelling at Boffin. It all ends with Rokesmith getting fired and Bella vowing to walk away from Mr. and Mrs. Boffin forever.
Before Rokesmith goes, Bella apologizes for any trouble she has caused him and any insults he's had to endure because of her. She's grown up a lot since we saw her talking as though Rokesmith's love for her was an insult.
Once Rokesmith is gone, Bella admits to Mr. and Mrs. Boffin that she has come to love him. And with that, she walks away from the Boffins (and from her personal fortune) forever.
Bella leaves the house and thinks about how nice it'll be to visit her poor father.