Dude is all "wish there was something I could do" but there is, there obviously is. You can take her off the pedestal everyone has put her on. Date her, publicly. Take all the heat that comes from it. What they hurl at you is now pressure that isn't on her. It sucks, because Japanese culture fucking sucks ass when it comes to jealousy and false entitlement towards others, but if you want her to not have to put up a façade that makes her miserable, then man the fuck up and take that weight off her shoulders.