[Undyne's smile fades the more and more Alphys explains, the more and more upset Alphys is clearly getting. She focuses on the important things and tries not to freak out a little - Alphys has been here a long time? It's dangerous? Alphys has been alone, in this dangerous world, without her?

But she knows what to do - she needs to be calm. She needs to be supportive. Even if she doesn't entirely understand, even if all this talk of alternate dimensions and time working differently is a little beyond her, she needs to calm Alphys down. Staying crouched down to Alphys' height, she puts her free hand above Alphys' and gives her a soft, gentle smile.]

Alphy. I don't know how all this works, but... if you called me here... it's because you needed me. And I came to you because... because I'll always, always be there for you. No matter what happens with alternate dimensions or time travel or whatever... if you need me, I'll always come.

And I promise, I'll be safe. And you'll be safe too. This place might be dangerous, but you know me. There's nothing that can hurt me. There's no fight I can't win. So you're not going to hurt me. And you're not selfish, OK? Not for needing help. Not for needing me. Not for anything.

[Undyne bows her head, laughing under her breath.] I'm not real good at all this sappy stuff. But... that's the truth.