A Folkestone man rang his former girlfriend and threatened to burn down her house.
Jobless Liam Knight told her: "It's not a threat – it's a promise."
Knight, 26, of St John's Church Road, appeared before the town's magistrates on Friday for sentence after admitting sending a menacing message on January 8.
Miss Sara Tilther, prosecuting, said he had been involved in a year-long relationship with Laura Gardner but this had ended on New Year's Eve after a series of arguments.
She said Knight had discovered he was not the father of a child she had miscarried. He lived in the flat above her and she had received calls from him about the child.
"They were threatening but at first she didn't take them seriously. Then he said 'I am going to burn your house down – that's not a threat it's a promise'," she said.
Mr Will Nelson, defending, said Knight made a full admission to police.
"The way he reacted to the news that the child was not his was out of all proportion but he was very distressed by the news," he said.
"He no longer lives in the flat above her and has moved elsewhere."
Mr Nelson said Knight was out of work and was in receipt of Jobseeker's Allowance.
Magistrates gave him a 12-months Supervision Order with £145 costs. A Restraining Order preventing him from contacting his former girlfriend was imposed. He was also ordered to attend training sessions with the Probation Service.