New way to change root password with GRUB

It has been a looong time that I had'nt start my Gentoo computer.I started and I cannot remind the root password !
I tried Grub with changing  the mode ( 3 ) but it didn't work !

I solved it with this great paper :https://memo-linux.com/grub2-contourner-lauthentification-linux-mot-de-passe-utilisateur-ou-root-oublie/

In summary :

• Edit the GRUB command line with 'e'
• Replace ro by rw
• Add init=/bin/bash
• Then run with F10 

That's all !