At one point she was in a 10 year relationship with Lothar but for unknown reasons he left her one day and married another woman and the two had a son, Tjalve, together. This, combined with the villagers commenting that she'd been had by Lothar after the two had been together for so long, angered and upset her and in 1272 she planted a nithing outside her former lover's hut, cursing the son to the point he'd die soon if it wasn't lifted.
If Geralt comes along and investigates: Geralt learned Jonna had planted the nithing and went to talk to her to remove it. However, her price was steep: she'd remove it only if Lothar denounced his son and returned to her, which would mean him stripping his wife and child of honor and condemning them to poverty.
- If Geralt gets Lothar to agree: Lothar reluctantly returned to Jonna to save his son and Jonna tried to convince him he'd soon forget about Tjalve and she'd bear him healthy sons. However, Lothar told her point blank he agreed to return to her but not to love her.
- If Geralt decides to carve her name: Deciding it wasn't worth taking it out on the child, Geralt sided with Lothar and carved Jonna's name in the nithing, turning the curse on her and soon killing her instead.