You are supposed to have 2 different names from what I understand. It will tell you "this is not your true name" if you type the same name twice so basically type in any different name from the one you typed first and it is fine.
Not sure I'd call it an alias as it is the name the MC use and thinks as theirs, but yeah "true name" is different :) sorry if it sounds a bit vague but trying not to spoiler how the "true name" is used later vs the name you want to be called(the first you type in) hope you have nice day!
