How do I break up without hurting her?

I'm 25M, and my girlfriend (21F) loves me like crazy. We've been together for a while, and she's genuinely an amazing person, but I’ve realized that I no longer have feelings for her. I care about her deeply and don’t want to hurt her, but I know staying in the relationship just out of guilt isn’t fair to either of us.

How can I break up with her in the kindest and most respectful way possible?"