Dilroy Fernando, the chief executive officer of the Sri Lanka Rugby Football Union, said the International Rugby Board (IRB) and the Asian Rugby Football Union (ARFU) had earlier raised serious security concerns.
The two organisations were worried that renewed violence in the island's separatist conflict with Tamil Tiger rebels would affect the tournament in Colombo from November 3 to 10.
"We took pains to convince both the IRB and the ARFU on the conditions prevailing in Colombo," said Fernando.
"Our presentation was based on various international sporting events taking place in Colombo such as cricket tours despite negative stories."
Sri Lanka Rugby Football Union president Nimal Leuke, who is also the head of a police Special Task Force fighting Tamil Tiger rebels in the Eastern province, gave the necessary assurances, said Fernando.
The Asian meet is expected to attract 15 teams.
Bangladesh's cricket team completed a tour of Sri Lanka on Wednesday without incident