Don't use bank accounts on online transactions. Whatever you do, we can find a way to get information. Ooppsss. They, the hackers can get information.
The chance of someone getting your account and spending some money is pretty high but you need to keep something in mind. ALL payments from your bank account take a day or two to clear. They are also cleared on business days. This gives you ample time to call your bank and identify the transaction as fraudulent and have them stop it.
If you buy something online and there is not enough money in your PayPal account - PayPal will take the money from your bank account the very same day. Also my bank cannot stop "pending" transactions. They have to wait until it's posted before they can do anything. Best advice is to get a separate bank account for PayPal verification purposes and keep little money in it.
I guess in the end, it depends on which country the OP is from and from what I understand, Italy is not one country which supports Instant Transfer or eCheck so paypal cannot take your money off from your bank account.
If you need the extra security, get a Paypal security token. Its a little usb drive like thing that shows random digits that change every minute or so and you enter it at login, essentially making it take 2 factors of authentication to login.
https://www.paypal.com/securitykey Unfortunately, it does look like its US only or limited to very few countries.
The main thing is if a hacker hacks your paypal account and tries to change the email ids the primary email address will be sent a verification email after which you can change your email address. So a wise step would be you should put your paypal and the email id used as paypal password different. Incase your paypal gets hacked you can contact or reverse the password change