Assad's comments, published in Lebanon's pro-Damascus newspaper As-Safir, came as the European Union renewed sanctions against Syria while amending them to enable nations to provide more "non-lethal" and technical support to help protect civilians.
As-Safir said that Assad had met with unnamed Lebanese politicians in Damascus during which he assured them that Syria's future belonged to his camp.
"We are sure we will win, we are reassured by the political and military developments," Assad was quoted as telling the visiting politicians, the Lebanese newspaper said.
"We are convinced that the future is ours... Syria has the willpower to defeat the conspiracy," said Assad, according to As-Safir.
He said those "loyal" to his regime "represent the absolute majority of Syrians".
Since the outbreak of a revolt against his regime in March 2011 that later morphed into an insurgency, Assad has systematically labelled opponents and rebels alike as "terrorists" he says are funded and backed by the West, Turkey, Saudi Arabia and Qatar.
The United Nations says that nearly 70,000 people have been killed in the conflict so far, many in massacres, bombardments, under torture and through summary executions.
A report by a UN-mandated commission of inquiry on the Syria conflict released in Geneva on Monday said that both Syrian state forces and rebels were committing war crimes, though it said the government camp carried more blame.
At a news conference where the report was released, commission member Carla del Ponte renewed calls for the International Criminal Court to probe war crimes in Syria.
"The international community -- and the UN Security Council -- must take the decision to refer this to justice," said del Ponte, a former UN prosecutor.
"We suggest the International Criminal Court. We can't decide, but we are pressuring the international community to act, because it's time to act," she said.
The decision to refer the conflict to the court lies with the UN Security Council, where there are deep splits between Western members and Russia, a longstanding ally of Syria's regime, plus China.
China has backed Russia in vetoing Security Council resolutions that would have put greater pressure on Assad's regime.
Meanwhile a statement agreed by EU foreign ministers said the bloc's sanctions were renewed for three more months until end-May, while "amending them so as to provide greater non-lethal support and technical assistance for the protection of civilians."
The ministers' talks on Syria largely focused on a request by Britain, backed by Italy and a handful of EU allies, to lift an EU arms embargo barring the supply of weapons to the rebel coalition battling Assad's regime.
Though the arms embargo was maintained, the agreement to boost "non-lethal" support and "technical assistance" went some way to meeting Britain's calls for more support for the opposition Syrian National Coalition.
On the battlefront, rebel fighters on Monday pushed on with an assault launched last week to seize key airports in northern Aleppo province, and captured a checkpoint near Nayrab military airport, the Britain-based Syrian Observatory for Human Rights said.
Rebels also clashed with troops along the strategic Aleppo international airport road, Observatory director Rami Abdel Rahman told AFP.
The rebels are determined to seize airports in a bid to capture large stocks of ammunition from regime forces and put out of action the air force's deadly firepower.
Monday's advance is the latest in a series by the rebels since they captured last week air bases at Al-Jarrah, Hassel and Base 80 in Aleppo province.
A military source in Aleppo speaking to AFP on condition of anonymity said rebels on Monday also tried but failed to raid the international airport's fuel storage warehouse.
"The army fought off the raid," said the source, adding that clashes broke out just 200 metres (yards) away from the airport and were "very fierce."