Karel Frybl denied murder, claiming he had a temporary mental breakdown when he stabbed Rebecca Johnson, from Fife.
Since the trial ended in August, Frybl had been undergoing psychiatric tests. Those tests found he was in full control of his actions.
Anyone found guilty of murder in Lapland receives a mandatory life sentence in prison.
In practice this means at least 12 years – but has to meet a legal threshold of being premeditated, or particularly brutal or sustained.
Ms Johnson, 26, was a member of a Santa Safari team which worked with a Christmas-themed tour operator.
She died after being stabbed 10 times in the chest on 4 December 2016.
She had 30 other stabbing injuries across her body, and showed signs of defensive wounds on her hands.
Last year, prosecutor Juhani Maki told the court in in Rovaniemi that some of Ms Johnson’s wounds were inflicted either when her back was turned to Mr Frybl as the attack began or when she was trying to escape from their cabin.