It's
actually impossible to get the True Pacifist Ending your first time playing through, and it's justified in game. You have to get the neutral ending first. Even if you don't kill anyone during that playthrough, you'll get a neutral ending still. The difference is you don't have to play through it again, it'll just drop you at The End and tell you to go find Alphys.Also, the soundtrack is sublime.
It's great.
Also don't feel like you have to do a Genocide run because.... well you don't.
