The devotion and fear level of the majority of your slaves impacts their opinion when you first take on a new slave. So to make them more positively disposed and trusting of you, have a Penthouse full of positive and trusting slaves. Beyond that, I always cycle my new slaves through the clinic (1st priority) and the schoolroom (2nd priority) and have those facilities maxed out to the benefit of slaves. If a new slave gets healed in the clinic and educated in the schoolroom but comes out scared, I put them in the servant's quarters to do housework. Once they're accepting or better, I put them in the spa until they're no longer afraid. If they come out of the schoolroom and they're resentful or hateful, straight into the cellblock with them. If that doesn't improve over a few (5-10) weeks, I just sell them. I don't need that negativity spoiling my new slaves.