SINGAPORE - A property agent who misled a married couple into handing her a $316,000 cheque to demonstrate interest in a Balmoral Road apartment, and failed to disclose she was the owner, has lost her lawsuit to claim the money.

A High Court judge found Ong Keh Choo, who has 35 years' experience, to be "untrustworthy" and "opportunistic".

Ms Ong had sued American research scientist Paul Huntington Bernando and his wife, Vietnamese medical concierge Tran Hong Hanh, for cancelling the cheque after they found out about her non-disclosure.

Her case was dismissed by Justice Choo Han Teck in a written judgment released on Tuesday (Sept 3).

"I not only find that there was no contract between the owner and the defendants, on the evidence, I am of the view that Tran was induced to give the cheque to Ong by reason of Ong's false and misleading representations."

The judge said Ms Ong had misled Ms Tran into thinking that she and her husband were complying with a normal process for the sale and purchase of a property in which the cheque was only "for show".

Ms Ong has since sold the apartment to another buyer for $3.82 million.

The dispute between her and the couple, who are Singapore permanent residents, arose on Oct 6, 2017, when Ms Tran responded to Ms Ong's advertisement for the sale of the flat. The couple viewed the flat the next day.

According to Ms Ong, the couple was so eager to buy the apartment that they initially issued a cheque for the full purchase price of $3.16 million. She said she advised them to reduce it to 10 per cent in exchange for an option to purchase.

Her case was that the couple knowingly entered into the option but were trying to get out of the contract after experiencing buyer's remorse.

On the other hand, the couple said Ms Ong told them to issue a cheque "for show" only and assured them that she would not hand it to the owner.

Later that day, Ms Ong met Ms Tran alone and told her to sign a document to acknowledge the cancellation of some words. Ms Tran said she did not know she was signing an option to purchase the property.

She later showed that document to a lawyer and was told it was an option with "highly unusual" terms.

First, the option fee was 10 per cent of the purchase price - the value of the cheque - when the usual market practice was 1 per cent.

Second, the couple had to pay the remaining 90 per cent upon exercise of the option, rather than the typical practice of paying upon completion.

Third, the full sum was to be paid immediately to the owner rather than held by stakeholders.

Ms Tran asked Ms Ong to destroy the cheque but the latter assured her there was nothing unusual about it.

It was only after Mr Bernardo filed a complaint with the Council of Estate Agents on Oct 8, 2017, that the couple discovered Ms Ong was the owner, and cancelled the cheque.

Justice Choo accepted Ms Tran's version of events, that Ms Ong had assured the couple the cheque was "for show" and had gotten her to sign an option without telling her what it was.

The judge accepted that Ms Tran, who appeared "guileless", was buying a property in Singapore for the first time and was not familiar with the procedure.

As for Ms Ong, the judge said her failure to disclose her ownership of the property was a contravention of ethical guidelines.

Her excuse was that Ms Tran had not asked, but the judge said her non-disclosure was an "active deception", pointing to text messages in which Ms Ong referred to the owner as a third party.

Ms Ong's persistent refusal to acknowledge that the terms of the option were unusual also detracted from her credibility, said Justice Choo.

She insisted that there was no "normal" option fee and refused to admit that paying the full purchase price upon exercise of the option was disadvantageous to the buyer.

"Her repeated refrain was that the transaction was unusual because Tran wanted it to be so. All this created the impression of an opportunistic owner taking advantage of an unsuspecting and ignorant buyer," said the judge.