How to add and check for a confirm password to Sign Up via Parse

On my sign up page I want users to confirm the password they chose using a confirm password textfield. I am using Swift.

Here is my code for my Sign Up

    if(newUser.password != self.confirmPassword.text){


            let alertController = UIAlertController(title: "Sign Up Failed", message: "Sorry, your Passwords were not matching.", preferredStyle: .Alert)


            let OKAction = UIAlertAction(title: "OK", style: .Default) { (action) in
                // ...
            }
            alertController.addAction(OKAction)

            self.presentViewController(alertController, animated: true) {
                // ...
            }
            }

This is in my @IBAction func confirmButton(sender: AnyObject)

Edit:

I am not getting an error, Parse still sign ups users if I just fill out a two different passwords or no password at all.

Thanks.