To answer the question and not discuss your private life or your relationship as most seem to want to do for some reason, the consensus these days when it comes

To answer the question and not discuss your private life or your relationship as most seem to want to do for some reason, the consensus these days when it comes to the most Windows-like experience seems to be Linux Mint with Cinnamon. ( Others have said the same already from what I've seen. ) If you want options and customization and are willing to spend serious time to set it up, then yes, KDE beats everything else and you can probably have it set up to her liking if she wanted to try it. I'd download a couple of live usbs, talk with her and see if she absolutely hates the idea of playing with them or not. ( Personally I'm not a fan of derivatives though, and would stick to an original distro; Debian, Fedora, Arch, SUSE ... Edit : Fedora has an official Cinnamon spin and people talk well of openSUSE's KDE. )