Your password is strictly personal and you should never share it with anyone, not even persons you know well. It is highly recommended to change password frequently.
If you receive an email asking for your password, you should not answer the request nor click any links in the email. Usually this would be a so-called phishing email from someone who unlawfully attempts to get hold of passwords with the intent to abuse them for unauthorised access. Instead, contact One.com's support if you receive an email regarding your password and you are uncertain on how to react.
One.com will never ask for your password for your web space or your email account. Should One.com need your password for trouble-shooting purposes, this will happen only by prior arrangement with you.