Yes, absolutely! ESET Password Generator is purely client-side JavaScript, so it only runs in your browser. Furthermore, the generator does not send the passwords it creates anywhere other than to your device’s clipboard, and it only does that if you choose to copy a specific, generated password.
The tool also follows the Digital Identity Standards set by the US National Institute of Standards and Technology (NIST), allowing you to generate a potential new password with the desired length and complexity parameters by choosing the ASCII character groups used, in any combination of uppercase letters, lowercase letters, digits, and punctuation marks and symbols. ESET Password Generator can thus produce a wide variety of non-dictionary, hard-to-guess passwords that would take an intractably long time to brute force.