She has just learn a new way of being generous not only to her friends but to all the people she meets. Sweetie Belle and her parents were in a trip but accidentally don't take her with them.
She thinks they forgot her, which upsets them.
"How could they forget me? (angry)"
However she gets a big surprise when she sees them going back for her. She learns not to make conclusions without having evidence and prooves. Similar to the lesson Pinkie learned in episode 24 of second season.
"Never make conclusions when you are angry" says her to Sweetie. Which she does not understand so well yet she accepts the teaching of her generous sister.
During the trip, her parents make a sudden stop.
"Mommy what's up?" R "Why did we stop? Is everything alright" S
They seem to be worried but at the same time a cheerful smile stands on their faces.
"Fine and dandy, dear" the mother says. "It is something we would like to give you, but since the gift is for you two, it's up to you two to decide"
Sweetie Belle feels anxiously excited and wants to know. Rarity the same but her excitement is more internal so she doesn't jump as much as her sister and does not express it so much, but it is as big as or bigger than hers.
"Why! Then what is it?" "Yes! Yes! Show it to us"
Both parents smiled.
"For you Rarity, which one? A place to live in Canterlot or three councils" Said their father. "And for you Sweetie Belle, which one? Anything you want or the three councils"