It is a sign that she respects your running ability and has thus asked you to help by running with her so she runs long enough. Assuming you are in better running shape than she is.
So help her out by running with her, at her pace, for however long she wants to go. Talk about what she wants to do/goal of the run before starting. The conversation should primarily be about her on the run, not yourself.
You will have to see how it goes during the run and judge if there is a sign of anything else. Don't go into this with expectations. You can have hopes, but that is about it for right now.
This is just an easy chill run. If you want to train do that on another day or another run.
If it is going well during the run invite her out for something to eat after. We want pics and a link to a strava file so we know it happened.