The first thing to be aware of is that rewrite rules donāt āchangeā URLs per se. They enable the alternate, clean version of the URL. If you type the ugly URL into the address bar, itāll still work. Rewrites make it so that you can also type the pretty URL into the address bar, and itāll work too.
With that cleared up, probably all you need to do is remove the backslashes.
RewriteEngine On
RewriteRule ^property/([0-9]+)/?$ view-property.php?pid=$1 [L]
I also removed the RewriteBase and the NC. Neither of them were causing your problem, but you donāt need them.