Please,help me find a proverb that fits with the idea that we cannot judge people based on their phisycal appearence.
You can't judge a book by its cover.
Beauty is only skin deep.
These are both very well-known sayings.
I'm not a teacher, but I write for a living. Please don't ask me about 2nd conditionals, but I'm a safe bet for what reads well in (American) English.