Would you rather.... ((I swear autocorrect corrected you as HIV and I was like WTF????!!!))

Erase Italy's memories of Holy Rome, but give Germany back his? (Italy wouldn't remember him.)

Or...

Tell Italy that Germany is Holy Rome, but erase Germany's memory's of him being Holy Rome? (Germany wouldn't be able to remember anything, the memory would be gone for good. Plus Ita would cry 5-ever.)