The couple also said they would seriously think about moving back to Zimbabwe as there was no place like home.
The couple initially moved to South Africa because the business environment was tough under former President Robert Mugabe's rule.
"There were a lot of challenges there. That's why we moved here."
A Zimbabwean engineer, who has been working and living in South Africa, said he was very excited about Mnangagwa and the revitalisation of the Zimbabwean economy.
"We came here to hear what his ideas are about the business people from Zim that have established businesses here in South Africa, what plans he has for us back home," said the engineer who also did not want to be named.
The engineer said he was more than ready to move back home because there was no place like home, and added that he wanted to be part of the refreshing of the Zimbabwean economy.
"This is a new renaissance for Zimbabwe."
The new president was a long-time ally of Mugabe, and his critics say he is also a hardliner from the ruling ZANU-PF party with a record of alleged graft and repression in Zimbabwe.
As he spoke, a group of fewer than 20 protesters chanted outside the embassy building over Mnangagwa's role during the early 1980s killings of perceived political dissidents in a campaign known infamously as Gukurahundi.
An estimated 20 000 people were killed by an elite North Korean-trained military unit. At the time Mnangagwa was a security minister under Mugabe.
"How can we work with the killer?" shouted one protester.
Two others carried giant pictures of dead bodies with gruesome cuts and burns.
Another protester yelled: "There's no difference between Mugabe and Mnangagwa."
Mnangagwa met South Africa's President Jacob Zuma and was also scheduled to meet ANC's newly elected leader Cyril Ramaphosa.
The South African presidency said Zuma and Mnangagwa "have undertaken to strengthen economic trade and cooperation between South Africa and Zimbabwe".
Mnangagwa said his government had reviewed investment laws that forced foreign companies to cede a majority stake to local investors and spooked investment.- News24