It's really easy to look back and think about what we could have done... if we'd just been faster, or known more...

But living like that won't bring anyone back, either. I don't think she'd want you to feel guilty - I know she wouldn't, because she wouldn't be your Persona otherwise.

[Okay, she doesn't really know that for sure - the Persona isn't another person's spirit, it comes from inside. But she's never met someone who had a Persona solely to give them guilt.] She's made your soul stronger.