There isn't even a 3DS emulator, so even if someone had the rom you can't play it on your computer.
So if you want to play ORAS... buy a 3DS. =p Or a 2DS (or just a used one), they're not that expensive these days.
Not much other discussion that can come from this, so I'll close. Please also note that you are not allowed to ask for ROMs on these forums.