The 32-year-old's trial begins Thursday, but she told television show "Inside Edition" she believes she won't be convicted of the killing of one-time boyfriend Travis Alexander.
"No jury is going to convict me," Arias said. "Why not? Because I'm innocent. You can mark my words on that. No jury will convict me."
Investigators said Arias stabbed Alexander 27 times, slit his throat and shot him in the head June 2008 at his Mesa home.
She has pleaded not guilty to first-degree murder, ABC News reported Wednesday.
Alexander's friends and family said he tried to break off his relationship with Arias, which began six years ago when they met at a work conference. Alexander friend Dave Hall said Arias was stalking him in the months before the slaying.
"There's nothing about her that I see in marriage material -- or wife material," Hall said Alexander told him. "But it's hard to say no to a woman that sneaks into your house, crawls in your bed and tries to, you know, seduce you."
Arias originally said she wasn't at Alexander's home the day of his killing, but later changed her story and said she saw two men attack him. She now says she killed Alexander in self-defense because he was allegedly sexually and physically abusive toward her, ABC News reported.