It's really hard to make out what she said but I think she said "I can't go back to the start" and "I'm only gonna deal with them all." I hope someone can translate the subtitles.
I translated the subtitles for you. Here you go:
Vergil: Your thought about this place...?
Dante: I've been here before.
Vergil: Together with our mother, yes.
Dante: Tell me all about it.
Vergil: Let's talk about a legend. Within this world angels and demons have always continued to quarrel with each other.
Mundus: To insult a God, that's......
Kat: I did kill demons, but there are still large crowds of them left. To destroy all of them is our job.
Dante: Should I do a self-introduction first? I am Dante.
Vergil: 9 millennium years ago, the demon boss got replaced. By the trusted friend of the superior powerful boss...
Dante: Sparda, you mean?
Dante: We two are the children of an angel and a demon. Demon father and an angel mother...
Kat: I have a way out. Taking a walk in Limbo in an out of body experience.
Vergil: That is in existence in Limbo.
Kat: Let's meet there. See you again, Vergil.