Going to church for a loved one?

In case this isn’t abundantly clear, I am an atheist. My grandmother is a devout byzantine Catholic. I gave up lying to her about believing in god many years ago. She asked. A LOT. So now I try to avoid the subject with her, because I know that she feels hurt by my beliefs.
Yesterday she asked me to start going to church with her. And, it isn’t that I care about going into church, I’m certainly not afraid I’m going to burst into flames or anything absurd. I’ve been to church with my grandmother more times in my life than I can possibly count. But she was practically begging me to go, and I know this isn’t about going to church. This is about me believing in god… and I just don’t feel like it would be right to fake that. I really don’t want to hurt her, but how do I stand up for what I believe without doing that?