Rachel Kolisi hopes her high-profile marriage can help to change minds in a still-divided country,

Rachel on Siya

My family loved Siya from the get go but I do understand there are a lot of challenges in South Africa when it comes to mixed race relationships. I tell girls love will survive everything

Every day Rachel Kolisi receives messages from young South African women desperately seeking her advice. The correspondents are usually white girls who have fallen in love with black or Cape coloured men, just as Kolisi did. Each woman receives a personalised reply, despite life becoming “crazy” since her husband, Siya, led South Africa to World Cup glory in November.

Although apartheid ended 26 years ago, mixed-race relationships are still considered taboo in South Africa, but, after the success of Siya in leading the Springboks to the William Webb Ellis trophy three months ago as the side’s first black captain, at least a dialogue has begun.

“My family were incredibly supportive and loved Siya from the get go, but I do understand there are a lot of challenges in South Africa when it comes to mixed race relationships,” Kolisi says, in her first interview for a British newspaper. “I try to encourage them [the girls who write to her] as best I can, but it is obviously a very personal and touchy situation. I always try to say that love is always going to survive everything.”

If South Africa is in need of a few fairy tales, the Kolisis (right) provide one, flourishing as a mixed-race couple with four children. They have a son, Nicholas, and daughter, Keziah, and adopted Siya’s younger half-brother and sister, Liyema and Liphelo, the children of his late mother, in 2014.

Kolisi gave up her job in marketing to look after their growing brood. “I have all of the different moods at home in a whole day – I have got the teenager and I have got a two-year-old with tantrums,” Kolisi says, with a laugh.

“I am tested daily, that is for sure.”

Motherhood is just one strand of her story, however.

Kolisi is now making a name for herself as a women’s rights activist, at a time when violence against females has reached epidemic levels Africa. Official figures suggest at least 137 sexual offences are committed every day in the country, while femicide rates are five times the global average.

Shortly before the World Cup, Kolisi took part in a march against gender-based violence, in which thousands gathered across the country, dressed in black and purple, to protest at the lack of action by the government.

“The abuse of women in South Africa is through the roof, and there is an increase in the amount of women being raped,” Kolisi says. “It all started with a girl [Uyinene Mrwetyana, a University of Cape Town student] who was raped and murdered in a post office. South Africans, I felt, had lost hope and we were all walking around more fearful, especially the women in this country.

“I think the World Cup really instilled hope again. There was unity like I have never seen before. I was privileged enough to be a part of the bus tour in Cape Town and I have never been able to experience South Africa like that ever before.”

She is, however, conscious that a World Cup triumph, no matter how memorable, cannot be a driver for change by itself. “Change in South Africa should not rely or be dependent on a rugby team’s shoulders,” she says. “All of us as South Africans need to be able to go out and do something.”

For her part, Kolisi is using her profile to launch a business, Rise, which provides motivational talks and health and fitness support to women. Her hope is to take the business to Britain this year, though she is not turning her back on her country.

“Even more important than going abroad, we are going into the communities around South Africa where those women are not even aware of the fact that their bodies are not products,” she says.

“They are basically brought up believing that their bodies are products that they will use to get income or food for the night.

“That is what they use their bodies for. Being raped in those environments is the norm that is going to happen, and you just have to deal with it as a woman. We want to teach women about their bodies and challenge them to go out and do their own things.”

Kolisi knows that her husband, through his position as Springboks captain – a position which rivals that of the president when it comes to influence in a rugby-mad nation – can also wield immense influence, even if she finds it difficult to square his current status with her first impressions of him.

“It was a dinner with some mutual friends and I wasn’t a fan of his,” she reveals. “I thought he was quite rude because we came late and he was sat in a corner, he didn’t get up to greet us. I wasn’t impressed at all. I really didn’t think much of him until we became friends and I realised he was a nice guy and I thought maybe I was being a bit hard on him.”

Kolisi grows more serious when she contemplates how her husband’s legacy can impact a generation of impoverished black children. “If you look at a little boy who is living in a township, he probably feels like he hasn’t got any opportunities.

“But now with Siya, who was in the same place, that child can truly begin to dream again.”