You can change the number of password attempts using profiles. These enable you to set various password properties, such as the how many times they can get it wrong, how often it expires, etc.

To allow them unlimited incorrect password tries, set the failed_login_attempts to unlimited:

create profile umlimited_attempts limit
  failed_login_attempts unlimited;
 
create user u identified by u;
alter user u profile umlimited_attempts;

But...

Limiting the number of password attempts a user can make is A Good Thing. If you disable it then you make it easy for someone to figure out the password by brute force. This is A Bad Thing. Particularly if you're using weak passwords.