A judge is setting out whether the murder case against Shrien Dewani, who is accused of arranging the murder of his wife Anni, should be thrown out.
It is alleged UK businessman Mr Dewani organised a hitman to kill her on their honeymoon in South Africa in 2010.
But defence lawyers claim the prosecution case has been weak and inconsistent and should be thrown out.
Judge Jeanette Traverso began announcing her decision at the Western Cape High Court at 08:00 GMT.
She has been considering both sides of the argument since 25 November.
In calling for the case to be dismissed, defence lawyers said the evidence of taxi driver Zola Tongo, the state's main witness who is serving 18 years in jail for Mrs Dewani's murder, was unreliable.
Judge Traverso began by saying: "It is crucial for the state to prove that Mr Dewani entered into an agreement with Zola Tongo the taxi driver."
If they could not, then there would be nothing linking Mr Dewani to the murder, she said.
But she told Western Cape Crown Court that Tongo's evidence was "riddled with contradictions" with his evidence "highly improbable".
"Discrepancies were a theme going through Mr Tongo's evidence," she said.
"In some instances evidence makes no sense and the explanations are poor."
Tongo has told the court he was paid by Mr Dewani to organise the murder and prosecutors say he "never strayed from the crux of his evidence" about the murder plot.
The family of Mrs Dewani, from Sweden, said last week it would it be a "nightmare" if the trial did not continue.
Her brother Anish Hindocha said: "It will be a terrible rejection after a four-year wait if we as a family do not hear the true story.
"He [Shrien Dewani] has said so many times that he wants to clear his name... [the trial] is an opportunity to clear his name."
Mrs Dewani was killed during an apparent carjacking when Tongo drove the couple through the Gugulethu township in his taxi on 13 November 2010.
Mr Dewani was released unharmed but his wife was driven away. Her body was found in the abandoned taxi the next morning. She had been shot.
He denies the charges against him.