Once Singh was outed - after the girl made some mention of the relationship to an aunt - Singh claimed there was no sex and that the messages were just "texting", said the judge, describing the claim as "untenable".
A jury saw through the denials in court earlier this year, he said, and found Singh guilty on 18 charges, including the one of rape in June 2018, the rest of the charges being unlawful sexual connection and committing indecent acts.
Judge Collins said the fact Singh had no previous convictions was counteracted by the duration of the offending, and there could be no discount from the "starting point" he used for determining the sentence.
While the Crown had not sought a minimum term of imprisonment, the judge said he had considered it. He said the time in jail would ultimately be determined by the Parole Board, and he had "no doubt" Singh would be deported on release.
"There are no mitigating factors at all," he said.
Having heard victim statements read by the girl's mother, by a support person on behalf of the teen, who was in court throughout, and by Crown prosecutor Clayton Walker on behalf of the girl's father – each describing the impact on the girl and turmoil for the family – Judge Collins said he had noted during her appearance as a witness in the trial that she was a "bright, bubbly, kind teenager".
He told the girl's mother - it was "a fractured family" as a result of Singh's offending - that the teen was a "most impressive young woman" and he admired her for her courage.