Returns on investment in the infrastructure and information and communications technology sectors in South Africa and Africa in general are virtually guaranteed, Deputy President Cyril Ramaphosa told investors.Addressing a session of the World Economic Forum on Africa in Kigali, Rwanda, yesterday, Ramaphosa said ''infrastructure has been a key economic driver in South Africa and in the region".The forum is exploring ways for African countries hard hit by the slump in commodity prices to kickstart growth through digital transformation.Ramaphosa reassured investors that South Africa was open for business."Investment in infrastructure has stimulated economic activity; therefore there are returns to be made for investors in infrastructure in South Africa and Africa," Ramaphosa said.He added that South Africa had found innovative ways of partnering with the private sector, especially in energy, and that this had opened new opportunities for private- sector investment.He also encouraged investment in connectivity through technology and digital solutions and said this should be a priority for African economies.Nelson Mandela's widow, Graça Machel, said at the WEF yesterday that while many want President Jacob Zuma to step down after the courts ruled that corruption charges against him be reinstated, he will remain in place until the ruling party wants him to quit.Said Machel: "The ANC doesn't want to open a hand for him to go. For Zuma, if the ANC doesn't take away his position he will not go."..