Hikaru is really innocent and a good child, when Kira realized that, she felt bad for just dating her to let off some steam. Kira is not a bad person but now that she has fallen for Hikaru of course she is not trying to cause more problems for her.
Don't worry It doesn't. It has some parts with a bit of drama but the web novel probably is one of the most heartwarming and cutest ones I've read alongside with Adachi to Shimamura (Actually Imo I consider both of them to be very similar).