Where can i get a real, authentic, japanese sword that would cut someone in half with ease?...?

Question:

and dont just google "real swords" or something, i want REALLY REAL ONES, not crap pieces of junk even if theyre sharpened.

Answer:

You might find one at a museum in Japan.

You can't buy a gun in Japan, so obviously you can't buy a sword that can cut someone in half.

Raid a museum. I dare you.