A junior is someone who has put time and effort into learning our programming language, but may not have previous industry experience with it. After speaking with them, I'm either convinced or not that given a reasonable burn in time they can become an independent and productive member of the team. I like to see a work history with other stacks of course.
There's really no concrete basis on which to judge what anyone is truly capable of, especially in our industry, sometimes it comes down to giving someone a fair chance and hitting the eject button if it isn't working out.
As a remote independent person who hires other remote independent people, on a contractual basis, I think I'm allowed to take more humanitarian liberties when I have hiring decisions to make, due to the structure of remote work and the qualities that independent people tend to have.
Hope that helps.