I’m sorry that you’ve forgotten the password – but the thing is there is “only one main password to log in and to manage encrypted files/folders”!
Unfortunately that’s precisely the password you’ve forgotten. We do many things to reduce the risk of this happening, but still it does in a very few cases.
We show the password when you set it by default, since usually you’re alone when you do set the password, and then you get visual confirmation that you’re typing what you’re expecting to type. Then we make you type it twice. Finally, you have to type it once again a third time to sign in and start encrypting files. We do try to make it as safe as possible, but in the end we’re offering strong password based encryption. If the password is lost, so is the data. That’s what encryption is for.