The court heard that the threats were made by Thomas McConnell, aged 28, over a drug debt that has since been settled.
He pleaded guilty at Dublin Circuit Criminal Court to threatening to kill or cause serious harm to Louise Sheridan in Ballymun on Aug 23, 2011.
McConnell of Dunemer Rise, Lusk, had initially denied the charge and other similar offences but pleaded guilty following a four-day trial last month.
He is also due to be sentenced in March for a second charge of having the head shop drug “snow blow” for sale or supply at his home on Oct 12, 2010. He was on bail for this offence when he threatened Ms Sheridan.
The court heard that the drugs were found during a garda search of McConnell’s house and had an estimated street value of €16,164.
McConnell has 82 previous convictions which include criminal damage, road traffic and possession of firearms.
Garda Brian Fahy told Colm O’Briain BL, prosecuting, that Ms Sheridan had noticed McConnell’s car outside her son’s school when she collected the child that day and deliberately took the long route home to avoid him.
When she and her son got to their house she saw McConnell sitting in a car outside and he asked her where a man she knew was.
When she said she didn’t know where this man was, McConnell started screaming at her; “Louise I will fucking killing you, do you not understand that?”
Gda Fahy said McConnell then got out of the vehicle and opened the boot showing Ms Sheridan a steel pole and a hammer before he said to her: “I will put you in the boot of the car.”
He then drove off after telling Ms Sheridan “I’ll be back later”.
Gda Fahy said Ms Sheridan felt very threatened by the incident and thought that McConnell would come back. She later moved house.
McConnell was arrested but maintained his right to silence during garda interview.
The court heard he has since written a letter apologising to Ms Sheridan but Gda Fahy said this has not provided the woman with any comfort.
Judge Patricia Ryan adjourned both cases to March and ordered a probation report and updated report from Coolmine Residential Treatment Centre.
Dominic McGinn SC, defending, said a current report from Coolmine stated his client excelled in his treatment there and was “an excellent role model”.
The report also said he was “honest, sincere and hard-working in his approach to his recovery”.
Judge Ryan is due to hear plea in mitigation from Mr McGinn on the next date.