The mother, whose name cannot be published under a publication ban, made the comments after David James Leblanc pleaded guilty to five charges in her son's case, the Canadian Broadcasting Corp. reported.
The mother said Leblanc's court appearance was the first time she had been in the same room with him and the experience left her shaking "uncontrollably."
"As a mother, I just wanted to just be alone with him," she said. "I just wanted him to suffer. Normally I'm not like that, but it was just overwhelming. I want him to suffer."
Leblanc had faced seven charges in the incident in which the boy, 16, was kidnapped and held in a home in rural Nova Scotia.
Leblanc pleaded guilty to sexual assault, forcible confinement, uttering a death threat, kidnapping and breach of conditions.
Charges of sexual assault causing bodily harm and administering a noxious substance with intent to cause bodily harm were dropped.
The teen was held captive for 10 to 14 days before escaping.