How can you tell the difference from an email from a potential customer and a scam email when they just say hello or can we chat?
Of course there is no way to figure that out
but a good rule of thumb is ignore such conversation because anyone who really wants to work/need you will probably ask better question and very open about it from the beginning.
I treat simple hi as they wanna check, Is this person is dumb enough or enough time to reply or not then they shows there true color
TLDR: don’t reply to such people, first ignore them and if they spam just block them and report them