WordPress wp_mail display error in sending mail

I made a custom registration page with validations on email, password and name are working fine. After registration an email will be sent together with an activation code which is also working. I wanted to display an error message in case if wp_mail does not send an email to users. How do i display error message if wp_mail failed?

Here is my code for sending mail:

        $user_id = wp_insert_user( ); //i removed this part because its a very long code but insert user works 
        $code = sha1( $user_id . time() ); /*for activation code*/
        $activation_link = add_query_arg( array( 'key' => $code, 'user' => $user_id ), get_permalink( get_page_by_path('register/success') )); //for server success page
        //$activation_link = add_query_arg( array( 'key' => $code, 'user' => $user_id ), get_permalink(772));
        $activate_url = '<a href="'.$activation_link.'">'.$activation_link.'</a>';
        add_user_meta( $user_id, 'has_to_be_activated', $code, true );
        //add_user_meta( $user_id, 'ja_disable_user', 2, true );
        add_filter( 'wp_mail_content_type', 'set_html_content_type' );
        //modify email sender
        add_filter('wp_mail_from', 'new_mail_from');
        add_filter('wp_mail_from_name', 'new_mail_from_name');

        $to = $email; 
        $from = 'noreply@test.co';
        $headers = 'From: '.$from . "rn";  
        $subject = __($locale['email_subject']);   
        $msg = __($locale['user_confirm_message_1']) ." URL: ".  $activate_url  ." ".  __($locale['user_confirm_message_2']) ." ".  __($locale['email_footer']);

        wp_mail( $to, $subject, $msg, $headers ); 

        remove_filter( 'wp_mail_content_type', 'set_html_content_type' );

        if( is_wp_error($user_id) ) {if( is_wp_error($user_id) ) {
            $err = 'Error on user creation.';
        }

            else {
            do_action('user_register', $user_id);
            $updated_date = current_time( 'mysql' );
            $wpdb->insert( 'client_detail', array('client_id' => $user_id, 'updated_date' => $updated_date), array('%s', '%s') );
            update_user_meta( $user_id, 'ja_disable_user', 2);
            $success = 'You're successfully register';
        }