WOW this is not only a stunning colour but an amazing rose. I would also love to know how to get this colour.
I use all natural colors at my job so it may be a little bit different, but i first make a deep purple and add more red to it. I hope this helps.
I used this color on a wedding cake I did last year. I used Wilton gel - 6 drops of Violet an one drop of black (in about 1½ cups of buttercream) and let it sit for a few hours. You can add more Violet or even royal blue for a deeper coler, add red for a warmer plum purple. It's mostly trial and error - but remember to let it sit a few hours so the color deepens before adjusting it