I love it how she takes her time to ducttape her horns so as not to hurt Helltaker

Well, even repentance and punishment through pain might require a bit of aftercare.

And she does view what she does as a good thing. Instead of reveling in being an evil demon lady that causes untold suffering in fire hell-pits. So it can make sense that she has a softer side when off duty. Plus, Taker did win her over by a bit of light complimentary flirting.