Xolile Mngeni, 25, sat with his arms folded as Judge Robert Henney told a packed courtroom in Cape Town Mngeni has come across as a merciless and evil person, South Africa's Eyewitness News reported.
Throughout his trial, Mngeni has maintained his innocence in the killing of 28-year-old Anni Dewani.
Her husband Shrien Dewani is fighting extradition to South Africa.
Dewani, who is being treated for depression at a psychiatric hospital in Britain, is accused of orchestrating the murder of his bride while the couple was vacationing in South Africa.
Man spent 15 hours in jail for plugging electric car into an outlet at a school
Florida bear attack: Black bear mauls woman's face