Strange characters on wordpress site – Not UTF8 Issue

What is your database encoding? Try to switch to utf8mb4.

Alternatively, try to add one of these lines in your wp-config.php file:

define('DB_CHARSET', 'latin1');
define('DB_COLLATE', '');

or

define('DB_CHARSET', 'utf8');
define('DB_COLLATE', '');

or

define('DB_CHARSET', 'utf8mb4');
define('DB_COLLATE', '');