Just finished my first run. I'm a bit confused about the hangouts.

Hello, I just finished my first run. I guess it was neutral (I guess? Correct me if I'm wrong), I killed just one monster at the beginning, but otherwise I spared everyone. I killed flowey. I wanted to hang out with Undyne and Alphys, but Undyne doesn't wanna talk to me because of my one kill. Do I have to do normal reset or true reset for Undyne to speak with me on my next playthrough? Thanks.