"We have embarked upon a new phase in our relations," Faruq al-Shara said after meeting Lebanese Prime Minister Fuad Siniora on the sidelines of a gathering of European leaders with their southern neighbours in Barcelona on Monday.
"We want to open a new page," he said, adding that Syria "wants to see security and stability in Lebanon".
Siniora agreed that progress had been made.
"We want to have healthy and strong relations between the two countries," he said.
Syria has been under international pressure after the UN Security Council demanded Damascus's full cooperation with an investigation into the 14 February car bomb killing of al-Hariri in Beirut, amid suspicion that Syria was involved.
Al-Shara said Syria would provide that co-operation.
"On Lebanon, Syria is committed to collaborating with the international commission of investigation and resolved to uncover the truth behind the assassination as both Syria and Lebanon, as neighbouring and independent peoples, have a major interest in doing so."
Al-Shara added that both countries were allies "whose common interests are unlimited".