What is allice cullens real name?

Rosalie's real name is Rosalie. I think you mean Alice. Alice's real name is Mary. Her middle name is Alice and her last name (as a human) is Brandon. Mary Alice Brandon. When she married Jasper, it became Mary Alice Brandon Cullen. But she still goes by Alice.

Rosalie Cullen's real name was Rosalie Lillian Cullen (this is on the biography on Twilight Lexicon.com).