New User Approval

You need to add_action two time for this. One at the time of user registration & second when user tries to login.

function wpse_149067( $user_id ) {

    if ( user_can( $user_id, 'tutor' ) )
        update_user_meta($user_id, 'verified_user', false);

    if ( user_can( $user_id, 'student' ) )
        update_user_meta($user_id, 'verified_user', true);
}
add_action( 'wp_login', 'wpse_149067_check_user', 10, 2);

function wpse_149067_check_user($user_login, $user){
    $user_id = $user->ID;

    if ( current_user_can( $user_id, 'tutor' ) && false == get_user_meta($user_id, 'verified_user') ) {
        // Do your stuff here 
        // eg: echo 'Please verify your account ';

    }       
}

?>