I'll leave it to you Sect; I'm no good with love stuff. :ohdear:
Gee, I'm glad that I'm considered the love guru around here :|
EDIT: Also, personality-wise, Konngara is a bit too serious and reserved for Sanae, who is more lively and openly displays her quirks. Kogasa's playful and surprise-ful (how else to put it?) nature goes hand-in-hand with Sanae's. It seems fitting that Sanae should view Konngara as a good, reliable friend rather than a romantic interest.
See, here's good discussion material.
This is my suggestion: talk to Konngara, first, find out why she likes Sanae. This is a pretty big bomb that she's dropped on Sanae, after all, so Sanae will be stumbling and trying to figure out what's going on. Asking Konngara questions like "why she likes her" and "since when" and "why did she tell her now" will allow Sanae to buy time and composure, and it will let Konngara be proactive for once.
Then, if we still don't know what to do, tatsukete Satori.
EDIT: Also, forgot about this: Guy, it's not a bad suggestion, entering a command to find out what Sanae thinks about Konngara, but the problem is that
we're the ones that have the most control over how Sanae thinks about Konngara, not the parser. We got a little info at the beginning, and we've been roleplaying as Sanae with Konngara since.