A Saudi Arabian diplomat, here on holiday with his family last August, asked for a better room than the one he had been given at his hotel on Sentosa.

While he was being shown the new room by a young intern, Bander Yahya A. Alzahrani, 39, restrained her against her will and molested her.

Alzahrani, who is with the Saudi Arabian Embassy in Beijing, was convicted yesterday after an eight-day trial of two counts of aggravated molestation and one of using criminal force.

In her brief oral grounds, District Judge Lee Poh Choo said the 20-year-old victim was an "unusually convincing" witness, and her evidence was consistent and sufficiently corroborated.

The incident came to light only because she had gone back to her office visibly upset, which triggered questions from her concerned colleagues. It took hours of cajoling for them to drag the story out of her, said the judge.

The victim was also afraid to reveal anything as the guest had said it was to be "top secret" between them.

The judge said the woman was young, naive and anxious to do well so she could obtain her certificate to enter the hotel hospitality industry. She had hoped to be employed by the hotel, the judge added.

"I believe this partly explained her mantra that she cannot offend the guest and hence her conduct on Aug 14, 2016. This was also her first time facing such an incident, causing her to be confused, lost, not knowing what to do and very embarrassed," the judge said.

The judge found her account to various people consistent, and corroborated by her colleagues and a security executive.

The victim, she said, had no motive to falsely implicate Alzahrani, a father of three, who the judge said was not a credible witness and not forthcoming during investigations. He left out any mention of hugging the victim, and it was only at a late stage that he came up with the explanation that she had stumbled and fallen towards him, so he had to place his hands on her back to support her.

The judge agreed with Deputy Public Prosecutors April Phang and Kenny Yang that there was no truth in the defence claim that the victim had conspired with other staff to bring these false allegations against Alzahrani to extort money from him - a rich diplomat from Saudi Arabia.

She found that the defence had failed to raise any doubt and convicted him of the three charges.

She adjourned the case until tomorrow for defence counsels Shashi Nathan, Tania Chin and Marianne Chew to prepare a detailed mitigation plea.

Alzahrani could be jailed for between two and 10 years, and caned on each charge of molestation; and up to three months and/or fined up to $1,500 for using criminal force.

It is believed that Alzahrani was not accorded diplomatic immunity as the offences were not committed in the country of his posting.