Linda Ayres said in the Circuit Civil Court that Mr De Ru, ex-director of Europlan Furniture, had reneged on payment of the money, which had been agreed in a settlement of partition proceedings part heard in court earlier this year.
Barrister Bernadette Kirby told Judge Matthew Deery that Ms Ayres, of Derry Park, Crumlin, Dublin, had agreed to sign over her interest in the couple's former home at 10 Dublin Road, Sutton, in return for the €52,500.
Ms Kirby said the money had never been paid and she was now seeking an order directing Mr De Ru to pay over the money. The court heard the couple also owned a property in Orlando, Florida, and that De Ru had previously settled Ms Ayres' interest in that property by paying her €70,000.
Part of the earlier settlement had included agreement on Ms Ayres' part to sign a 'Quitclaim' document releasing her interest in the Florida property to Mr De Ru.
It also included an agreement for her to collect from 10 Dublin Road, Sutton, her mother's china cabinet, a dinner service, Waterford crystal and other belongings.
Mr De Ru said Ms Ayres had "in blatant bad faith" delayed signing documents which had cost him a buyer for the Florida property, which he said was now worth only €95,000. Judge Deery, who said there was no real defence to the agreement to pay the €52,500, directed Mr De Ru to do so before December 20 and awarded costs against him.