"I am convinced that if both parties continue to be willing, we are going to achieve peace - a peace which will change this country," Santos said in a radio interview.
The Colombian leader added that he was "guardedly optimistic" that talks with rebels from the Revolutionary Armed Forces of Colombia (FARC) could even wrap up before May's presidential election.
Santos, a conservative, is running for a second four year mandate, from 2014-2018.
His political prospects are linked to success in the talks, which have gone on for more than a year. Re-election would give him the chance to bring peace to fruition in his conflict-weary Andean nation.
Negotiations between leftist rebels and the Bogota government resumes on Monday after a three-week hiatus. Talks have been under way since November 2012 to end nearly 50 years of armed conflict, Latin America's longest-running insurgency.

Dialogue between the two sides has proceeded in fits and starts. They have reached consensus on two issues – rural development and the political reintegration of demobilized rebels - but tough issues remain, including disarming the guerrillas.
Yesterday, a deadly motorcycle bombing blamed on the FARC, ended a month-long truce that had been a gesture of goodwill during the peace talks with the Colombian government that are taking place in Havana.
The attack killed at least one person and wounded more than two dozen.
Santos wrote on Twitter that the bombing was and "irrational and contradictory" act, coming as it did with peace talks under way.
The conflict has left hundreds of thousands dead and displaced more than 4.5 million Colombians.


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