Unconvinced his pregnant partner was carrying his child, a man went to a shed and got zip ties, a chainsaw and bolt cutters.
On the second trip he retrieved a blowtorch.
After the partner's wrists, ankles and thighs were tied together, the man dragged her to the bedroom with a woman's assistance.
"Do you want this chainsaw in your face?" the man said.
Starting it up in front of her, the man threatened to cut her head off if she did not tell the truth.
He then turned his attention to the blowtorch.
"You held the blowtorch toward her asking if she wanted to be burnt alive," Judge Jodie Wooldridge said in Brisbane District Court on Thursday.
The man had been with the three months' pregnant partner for about two years and they ran businesses together when the November 2022 ordeal occurred, the court was told.
"You harboured suspicions at the time that the baby ... may not have been yours. This was a source of tension between you and the complainant," Judge Wooldridge said.
"That of course in no way justifies your conduct."
The man had woken the partner up at 3am, making her watch CCTV footage he suggested showed her talking to someone else while he was asleep.
A woman who was a work colleague and also resided at the house did not discount the man's claims and started watching the CCTV footage on repeat.
Neither the man nor the woman accepted the partner's version of events and they took her car keys.
They then went to the shed.
The man came back with the tools while the woman retrieved electrical tape and wire, placing them in the bedroom.
"Tell me the truth. You are making a fool out of me. I just want to know what went on," the man told the partner.
When she maintained she was not lying, the partner was tied up and dragged to the bedroom by her arms.
The man first threatened to remove fingers with the bolt cutters before turning to the chainsaw and blowtorch.
The partner was restrained for about 15 minutes before she escaped and alerted police.
When officers arrived they discovered a small amount of cannabis and a pipe.
A domestic violence order was issued against the man by his partner only weeks before the incident, the court was told.
The partner's victim impact statement said the "situation has been blown out of proportion".
But Judge Wooldridge told the man: "I need to be clear ... this is serious offending".
The man had been given a possible diagnosis of borderline personality disorder and prescribed medication, the court heard.
He was also addicted to drugs at the time of the offending.
The man - now aged 34 - on Thursday pleaded guilty to charges including deprivation of liberty and threatening violence at night.
He was sentenced to 10 months in jail, with immediate release on parole on strict conditions.
The man is on remand for other matters.
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