RewriteRule ^/this-example-page$ this-example-page.html
Not quite! In htaccess the leading slash of the requested path is stripped. You also need the
RewriteRule ^this-example-page$ /this-example-page.html [L]
This code must be placed after your non-www/www redirect and before the wordpress internal rewrite(s).
On the left, what the user requested in the URL.
On the right, where inside the server the content really resides.
URLs are used "out there" on the web. Files are used "here" inside the server.
A rewrite is a URL to filepath translation.
A redirect is a URL to URL translation.