Passwords entered for connections etc. can optionally be saved between sessions by DbVisualizer. Passwords containing special characters such as ♥ can not be saved when the default encoding for passwords is used. More specifically DbVisualizer only supports characters in the 8859-1 character set with the default encoding; other characters are corrupted when saved.
To be able to save passwords containing any characters, you need to enter a Master Password. Please see the section Setting a Master Password for more information.