"This, for reasons not explained to me, came to the attention of the police," the judge said.
But despite police informing the man his victim was actually 15, he continued contacting her.
After the warning, he met with her again and gave her more alcohol, making arrangements with her to go to a hotel.
The victim has not fully begun to comprehend the significance of what had happened to her, her mother said in a victim impact statement.
Reading her statement in court today, the mother said the victim was a loving daughter and sister.
"She may have been an object of gratification to you, but she's the daughter that I have loved and cared for for the past 16 years."
The victim's family had seen her start exhibiting risky behaviour, self harm, and fall into substance abuse.
Her younger sister had started sleeping with a baseball bat beside her bed for fear of being harmed by the victim or someone the victim knew, as she became more volatile.
Now the victim herself has to sleep with a light on and is prone to panic, her mother said.
"[She] now sees all grown men as predators, only interested in her for their own sexual gratification.
"Your offending set off a chain reaction . . . [she] wound up down a very dark path where her sense of self worth was decimated."
Judge Bruce Davidson said the offending was low level, so declined to make an order that the man's name be added to the sex offender register.
The man applied for permanent name suppression on the grounds he could lose his job, but Judge Davidson refused the application.
It was part of the man's employment contract that he must inform his employer of a conviction, which he had not done yet. Judge Davidson said a suppression order would have the effect of "hiding" the conviction from the employer.
He said it would therefore be "wrong in principle" to suppress his name.
However the man's lawyer had been instructed to file an appeal to the judge's decision, meaning he still cannot be named until the appeal process is complete.
Judge Davidson sentenced the man to five months of community detention and 12 months of supervision.