The winger added to Rachel McLauchlan’s stunning opener to help Jo Potter’s side to a 2-0 win over Hearts.
The Light Blues lifted the trophy for the first time ever and Arnot - who signed a contract extension this week - was delighted to leave Hampden with the silverware.
Speaking to RangersTV: “It’s brilliant to end the season on a high and be cup double winners.
“Last week was really sore for us and no-one wants to lose the league at any time, but to lose it on goal difference was really hard.
“As a group we knew how good we can be and we came into this game with confidence.
“To get a good performance and the win was the most important thing.
“I think we were in control but 1-0 is never enough and we knew Hearts could be a threat on the counter.
“So for us to get the second goal is really important and then you can enjoy the last few minutes of the game.”
Arnot netted with four minutes left to make it a cup double to bring the curtain down on the season.
She added: “I was delighted to score.
“It was a great set up by Rachel Rowe so I could just step onto it and when it hit the corner, I just remember going to the fans and thankfully I didn’t muck up the knee slide!
“Jo has been a massive part of the success. She has improved us and we can take so much from this season.
“To win cups is great, but we want more and I think we can keep on learning under her.”