Why not both?

In Korean the phrase is a lot shorter so I'd prefer it in Japanese since its a lot longer. To be honest, it depends on where you want it done. If its coming down the arm, then in Japanese is more interesting. If its above your heart, then you should think of how small you want the characters to be. For Japanese, the characters would have to be very small.
I'm getting a red rose with a scorpion in the middle beneath my breasts. Same place as Riri's.. https://www.pinterest.com/pin/531354456009219372/
Writing I'd want later and going down one side of my body. Make sure you know exactly the position and the font and size. Think carefully.

Why in Japanese or koreean?