wpbd to connect to a VPS mysql database

You can create a new wpdb object, and then use that.

global $mydb;
$mydb = new wpdb( $db_user, $db_pass, $db_name, $db_host );

…and then use $mydb as you would the global $wpdb object.

Hata!: SQLSTATE[HY000] [1045] Access denied for user 'divattrend_liink'@'localhost' (using password: YES)