With a humility stemming from his party’s electoral disappointment, President Cyril Ramaphosa of South Africa was sworn in for a second term on Wednesday, conceding bluntly to the government’s failure to cure a nation that remains deeply divided and economically fraught in the three decades since the end of apartheid.

Facing the reality of governing in partnership with rival politicians, Mr. Ramaphosa, the leader of the African National Congress, issued a call for unity reminiscent of the father of the nation, Nelson Mandela. Mr. Mandela had stood on the same bluff of government buildings overlooking the capital, Pretoria, in 1994 and tried to rally a country looking to move past its collective trauma.

But if Mr. Mandela presided over a nation bubbling with the promise, Mr. Ramaphosa confronts the broken promise.

Voters punished his party, the A.N.C., in last month’s election, giving it just 40 percent of the vote, the first time it has failed to win an absolute majority since gaining power 30 years ago.

“Above all, the people of South Africa have stressed that they are impatient with political bickering and the endless blame game among politicians and political parties,” Mr. Ramaphosa said. “They want us to put their needs and aspirations first, and they want us to work together for the sake of our country.”

One-third of the parties in Parliament have signed onto a coalition led by the A.N.C. They include the second-largest party, the Democratic Alliance, which got 22 percent of the vote and has long positioned itself as the fiercest of the A.N.C.’s critics. The four other parties that have joined the coalition each won less than 4 percent of the vote: the Inkatha Freedom Party, the Patriotic Alliance, the Pan Africanist Congress of Azania and GOOD.