According to the indictment, the duo tried to extort money from the plaintiff and then stabbed him "with a knife or other sharp object".
The prosecutor charged them with attempted murder or aggravated assault.
However, the district court chose to acquit the woman and convict the man of aggravated assault.
Both have denied the acts.
According to the investigation, the plaintiff must have fled from the park near the cathedral where he was stabbed in the stomach to a youth home.
He was taken to Visby Hospital where he underwent emergency surgery.
Judged on several counts
The accused have claimed that they acted in self-defense.
But the district court does not find their stories completely credible.
The plaintiff's account also states that they should be "assessed with caution".
The 25-year-old is also convicted of harassment, fraud and attempted fraud.
The sentence was set at three and a half years in prison.
He must also pay SEK 80,000 in damages to the victim.