And on Feb. 14, Valentine's Day, she betrays some weariness with prison life and talked about looking forward to being freed from jail and offers to show Sollecito around Seattle when they are out of prison, including her favorite pizza place.
"Are you alone in your cell?" she asked Sollecito. "The thing about women's prison is there about 70 of us altogether at the maximum and we all live on the same floor, so all of us are mixed together regardless of the length or type of conviction.
"For instance in my very own cell I'm living with a drug addict, a thief and an accomplice to murder... if I have to get down to their crimes they are here for."
That letter is signed, "Your friend, Amanda" and includes a smiley face.
Knox's testimony was expected to be key to the case and Carlo Della Vedova, one of her lawyers, said Knox did a good job on the stand.
"I think also the message that came to the jury that there has been a lot of misinterpretation about herself as a personality as a person and also of the facts that have been misinterpreted and used against her," Della Vedova told ABC News Elizabeth Vargas.
He explained why Knox began her testimony in English and later spoke in Italian, and said it wasn't because she was rattled.
"In front of a jury, media all of us she thought maybe she would have difficulties, so she thought it was better to start in English in order to be acquainted with the room and so that's why she then switched to Italian," the lawyer said.
Knox's mother is scheduled to take the stand this Friday.
Della Vedova said her questioning will be limited to phone calls she received from her daughter.
"Amanda... it was the first thing that she did when she found the body. She called her mother as 20-year-old girls do," Della Vedova said.
Knox's father, Curt, told ABC News that he thought his daughter performed credibly on the stand. He said he had a too brief moment with his daughter when she completed her testimony Saturday.
"She took a big sigh of relief and said I love you and then unfortunately they took her away," Curt Knox said.