Melania Trump, then known as Melania Knauss, with boyfriend Donald Trump in 2004. [REUTERS]

The principal of Melania Trump’s old primary school knows juvenile behaviour when she sees it. And she has some advice for the candidate who once described his own campaign as “a little childish”.

“Melania is very wise,” Mirjana Jelancic says. “Donald should listen to her more.”

It’s a common refrain in Sevnica, a quiet industrial town of 5,000 nestled in a lush tree-lined valley on the banks of the Sava river in central Slovenia.

Melania Trump, then known as Melanija Knauss, grew up in Yugoslavia in the 1970s and ‘80s.

Those who knew Melanija Knauss as a child are proud that the soft-spoken hometown girl could soon be First Lady of the United States.

And they’re reluctant to publicly criticise Donald Trump, despite their concerns over recent allegations about his behaviour towards women.

Melania, now US First Lady in waiting, was born in 1970 in what was then communist Yugoslavia, the daughter of textile worker Amalija and car salesman Viktor, who friends say bears a striking resemblance to her husband.

“She was always very sophisticated, extremely well brought up in a very traditional way,” recalls Jelancic, her former classmate and neighbour. “In that respect she was different from us.”

If Donald was something of a troublemaker in his younger days, Melania was the opposite - a reserved and diplomatic presence on the playground outside the modest concrete apartment where she grew up.

“She was well spoken, she never swore if there were arguments between us,” says Jelancic.

“She always mediated, forged a compromise and unified us again.”

In their grade school days, the girls would knit gloves, sweaters and leg warmers as they flipped through the fashion magazines that inspired Melania from an early age.

“Melania never said she wanted to be a model, she wanted to be a designer,” says Jelancic.

“But I always had a feeling that Sevnica and Ljubljana would be too small for her.”

TOO RESERVED

In 1987, photographer Stane Jerko noticed Melania — by that time a high school student in Ljubljana — outside a fashion show waiting for a friend.

“She was a bit shy, but she learned very quickly,” Jerko says of Melania’s first ever fashion shots, described by the Trump campaign as test photos.

“The second time she was very good, like a model.”

Although they haven’t spoken in decades, Jerko has followed Melania’s career from afar. He thinks she would be a “marvelous” First Lady.

“I feel like she got a bit lost,” he says. “She is too reserved and she is too much in the background.”

Melania has kept a low profile since the summer, when her speech at the Republican convention was overshadowed by a plagiarism controversy.

It was her biggest moment in this election and it was an embarrassing distraction for her husband’s campaign.

In early October, a video shot in 2005 surfaced of Donald Trump making lewd comments about grabbing women’s genitals.

He was married to Melania - his third wife — at the time. It was followed by allegations that Trump sexually assaulted a number of women over the course of the past four decades. Trump vehemently denied the allegations.

In an interview with CNN’s Anderson Cooper, Melania defended her husband, calling the accusations against him “lies” and saying that he had been “egged on ... to say dirty and bad stuff”.

“I believe my husband,” she told Cooper, saying she had never heard Trump use such crude language, which she characterised as “boy talk”.

“But my husband is real. He’s raw. He tells it like it is,” she said, insisting: “He’s kind. He’s a gentleman. He supports everybody. He supports women. He encourages them to go to the highest level, to achieve their dreams.”

The latest allegations against Trump outraged many in this nation, which seemed deeply conflicted about the US election.

Proud as they are of Melania - who would be only the second foreign-born First Lady in US history - many Slovenians were alarmed by Trump’s abrasive campaign.

“Trump has horrific views on women and how they should be treated,” said Mia Janezica, a law student in Ljubljana. “Just because he has money and power, he can’t treat people like that.”

Melania’s old classmates were more diplomatic.

“These aren’t easy words for any woman to hear about her husband, but I know that she will know how to handle this,” said Petra Sedej.

Sedej recalled the more carefree high school days of the late 1980s, when the pair would hang around in Melania’s apartment in Ljubljana after their design classes finished.

“She was very funny, it wasn’t serious all the time,” she says. “We both liked fashion and design and we were both quiet girls. We didn’t like heavy partying or discotheques.”

LOCAL TEENAGER

 One night, she met a local teenager named Peter Butoln at the Horse’s Tail bar in the center of Ljubljana.

He wrote her phone number on the back of his hand, and said they began seeing each other shortly afterwards, taking trips to the sea on the back of his blue Vespa - a fashionable mode of transport in 1980s Yugoslavia.

The Trump campaign denied that Melania and Butoln ever dated.

In the early 1990s, Melania left Slovenia for good, ditching a university degree in Ljubljana for the runways of Milan and Paris.

In 1998, two years after she immigrated to the US, she met Donald Trump at a party at the Kit Kat Club in New York.

They married in a lavish ceremony at Trump’s Mar-a-Lago estate in Florida in 2005 — the same property where, one year later, a People magazine journalist who was there to write a story about the couple’s anniversary says Trump tried to force himself on her.

Trump and his campaign vigorously denied the accusation.