The Tahs secured a record-extending seventh Super W title.
NSW scored the first four tries of Saturday's final at Four R Stadium, racing to a 24-0 lead 10 minutes after halftime.
The Drua took almost an hour to post their first points, but any glimmers of hope were quickly extinguished as NSW replacement back Amelia Whitaker crossed twice in the following eight minutes.
The Waratahs scored six tries to three in the first Super W final played in Fiji. It was the third time the two teams had met in the final, with each team winning one encounter prior to Saturday.
The result completed a terrific turnaround for NSW, who lost back-to-back matches to Queensland Reds and Western Force in their last two round-robin games, before defeating Force in the semi-finals.
"I feel like rugby in Australia wrote us off, we lose two games and that's it for us and this is the response," Waratahs captain and flanker Emily Chancellor said.
"I couldn't be more proud of the way we played today," added Chancellor, who praised the local crowd for their energy before collecting the trophy from Fiji Prime Minister Sitiveni Rabuka.
The game was played at pace, with both sides looking to move the ball quickly, but NSW executed better in the first hour as the hosts made too many mistakes, including six lost lineout throws.
Prolific try-scoring winger Maya Stewart charged over unchallenged in the 19th minute, after quick passes unlocked the Drua's defence.
Stewart turned creator when she offloaded to fellow Wallaroo Miller for the Tahs' second try.
The home team twice turned down the option to kick for goal in the first half, but had a lineout throw stolen from the first penalty and couldn't breach the Tahs defence after tapping from the second.
Up 12-0 at the break, NSW doubled their advantage after Wallaroos prop and player of the final Faliki Pohiva crashed over and centre Rose Ferguson rounded off a fine multi-pass move by dummying her way through the defence.
Flanker Nunia Daunimoala scored the Drua's first try, but Whitaker's double effectively settled the contest.
Daunimoala bagged her second and No.8 Sulita Waisega also crossed, as the Drua battled until the end and showed what they could do when retaining possession.
"This has been a tough year, we've rebuilt from ground level again," Drua's season captain Bitila Tawake said.
"The goal for the club is to get (to) another grand final and we promise that we will get there again."
NSW forward Emily Robinson came off the bench to play in her eighth Super W final and seventh title-winning team.
The Waratahs will play in next Saturday's Super Rugby Champions final against the winner of New Zealand's Super Rugby Aupiki decider between the Blues and Matatu.
