After working on his mother via letters for a while, Edward is allowed back into the Ferrars fold. She deems him her only son (having disowned Robert), and allows him to marry Elinor.
However, even though he's back in the family, it doesn't mean he gets everything he was originally meant to have – Robert still receives his thousand pounds a year. Edward receives a sum of ten thousand pounds, just as Fanny did when she got married.
Edward and Elinor are pleased as punch, as they didn't expect that much. Now that they have an income, and a home provided by Colonel Brandon, they have everything they could possibly need.
The pair is married in the fall at Barton church, then they move to Delaford. Mrs. Jennings comes to visit ASAP, and everyone is quite content. The only thing they could wish for (other than better pastures for their cows) is for Marianne and Colonel Brandon to get married.
Everyone comes to visit Edward and Elinor, from Mrs. Ferrars to Fanny and John.
John, embarrassingly, says that he's pleased for Elinor, but he clearly would have preferred having Colonel Brandon (and his estate) for a brother-in-law.
Even though Mrs. Ferrars comes to visit, she's not a huge fan of Elinor. Against all odds, Robert and Lucy are restored to favor, and the treacherous Lucy becomes her mother-in-law's favorite.
Lucy's self-interested actions come to light; she clearly lured Robert into marrying her under the guise of discussing her relationship (at the time) with Edward. Robert is proud that he stole Lucy from his brother, but in fact, she manipulated both of them.
Soon Lucy becomes essential to Mrs. Ferrars, as much so as John and Fanny.
The Ferrars family politics are mysterious to everyone outside of the fold; despite being slighted by his mom, Edward is still happy with his circumstances.
Elinor is also perfectly happy – she and Edward are close to her mother and sisters, who come to visit Delaford constantly. Mrs. Dashwood also wants desperately to marry Marianne to Colonel Brandon. Everyone is for this marriage – how could Marianne not go for it?
Marianne, having come so far in her views and beliefs, has transformed completely. She slowly gives in to the steady affection of Colonel Brandon, and marries him.
Now, everyone is totally happy. Marianne is completely in love with her new husband, and he with her.
Willoughby is made unhappy by news of Marianne's marriage, and doubly unhappy by the fact that Mrs. Smith forgives him – doesn't this mean that she would have also forgiven him if he'd married Marianne? It turns out he could have been both happy and rich, if he'd only been more faithful to his emotions. However, we shouldn't feel too bad… he's doing OK. However, Marianne continues to be his vision of a perfect woman.
Mrs. Dashwood stays at Barton Cottage, where Margaret has grown old enough to dance, flirt, and have a suitor (fortunately for Mrs. Jennings and Sir John, who need some entertainment!).
Between Barton and Delaford, everything is right in the world.