I am a total newbie with probably a silly question

I will admit I know next to nothing about password managers. So, with that in mind, here is my question:

If people from the internet can steal passwords, then what is to keep them from stealing your master password (of your password manager)?

You can check security related questions here: https://help.bitwarden.com/security/
also do check: https://hackerone.com/bitwarden