The US Senate Foreign Relations Committee conducted the hearing to confirm Mrs Clinton's appointment as secretary of state.
Mrs Clinton said there would be change of policy towards Cuba under President-elect Barack Obama's administration.
She confirmed the new government would lift the US ban on travel to Cuba.
Mr Obama has already said he is willing to talk to the government of President Raul Castro in an effort to end 50 years of strained relations since the Cuban revolution.
'Smart power'
In her opening statement at the hearing, Mrs Clinton expressed a desire to strengthen America's relationship with its allies.
With 'smart power', diplomacy will be the vanguard of foreign policy
Hillary Clinton
Obama's balanced foreign team
Profile: Hillary Rodham Clinton
"America cannot solve the most pressing problems on our own, and the world cannot solve them without America," said the New York senator.
"We must use what has been called 'smart power', the full range of tools at our disposal," she added