Problems with registration

Hi!
I have a website, where people can registrate. When the contact form is completed, the site redirects them to a page, with some messages like “Succefully registration!”. Untill this everything it’s ok, but when i search in the Google to registration, this page is found there (this, with succesfully registration), which shouldn’t be visibile for anyone, only for those who had compelted the registration form.
What should I do, if I don’t want that page to be searcheble and visible for anyone who searches “registration”?
(this maybe simple for some users, but I need help)