Solution:
I don’t think the “province” is a default woocommerce checkout field, but here is an example you can use if you know the right “province” field name :
insert this into your functions.php file inside your WordPress theme.
add_filter( 'woocommerce_billing_fields', 'wc_cf_filter_state', 10, 1 );
function wc_cf_filter_state( $fields ) {
$fields ['billing_state']['required'] = false;
return $fields ;
}