Where can you find the wish tag Pokemon ruby?

Its Just An Answer!you go to mirage island and look for it. < that's all i heard in this website! i cant even find one :( i never even went on mirage island!

This is false, I don't know if you can get a skill tag there or not, but a Wish Tag is the tags on Jirachi's head, and it is impossible to get it, except maybe through hacking. It may have been a beta item, or a theorized item that didn't even make it into the beta, all that's left being the tags on Jirachi and the girl who talks about them.