I Turned the World-Destroying Villain into a Lovesick Fool

The Most Powerful Heroine + Brooding, Reborn Male Lead + Love and Hate + He Falls for Her on His Own + Hopeless Romantic

The System told me to save the villain, so I went.

The villain had been reborn. He trusted no one and guarded against me like a thief.

I couldn't be bothered to coax him, so I went straight to fighting.

As we kept fighting, he stopped trying to destroy the world and started spending every day figuring out how to make me look his way.

I just don't get it. How does an apocalyptic supervillain end up with a hopeless romantic streak?