Vernon Ruwhiu promised to manage 65-year-old Takangaroa Moanaroa's retirement savings for her benefit.
Instead, he took her savings and used them for his family's benefit after establishing a family trust - but not on terms agreed with Moanaroa.
The High Court has ordered Ruwhiu and two others to pay Moanaroa, who lives in Whangārei, more than $500,000 in total for breaches of fiduciary duty after Moanaroa took legal action to recoup her loss.
She met Ruwhiu at a seminar about mortgagee sales in 2003, at a time a property she part-owned in Whenuapai was to be sold under a mortgagee sale.
Moanaroa wanted to invest savings she had of $61,000 into buying a house in Whangārei for her retirement in 2006.