The password encryption in the PST file is very weak, and for each password-protected PST file, there are many passwords that can open it.
PstPassword provides 3 different passwords for each password-protected PST file. It’s possible that one of them will be the origianl password that you typed, and it’s also possible that none of these passwords will be identical to the original one. However, all 3 passwords provided by PstPassword will open the PST file without problems.
For more interesting facts about the PST password encryption, click here