@apoawaisoChae, @enmus & @necker sometimes it really is a good idea to search a bit before posting a question. This particular topic has been discussed to death several times over…
- Passwordless root access in qubes
- WTF?! Passwordless Root Access in VMs?
- How to setup root password in qubes?
- How to use the password authentication mechanism in Qubes OS?
- Qubes sudo / su / root Hardening - Development Discussion
- Qubes without root password ? Is it safe?
- Passwordless root
It is highly unlikely that this thread will produce anything that the others haven’t yet.
In the end you have the choice to either use passwordless root (the default and consensus of the core team), not use it and use qvm-run -u root instead or configure a dom0 prompt for it. So if it makes you feel better, go for it.
If there is any aspect of it you feel hasn’t been addressed in the linked threads above … let’s have it.