Have you made mistakes in your past that prevent you from entering the US? Being convicted of certain crimes may render you inadmissible to enter the US.
With a US waiver, you will be permitted to enter the US even though you have a criminal record. You must convince the American authorities that you are rehabilitated and that you no longer present a threat in your home country and to the American public.
Your application for a US waiver must be presented in the most favorable light possible.