My supervisor of over a year, I thought she was pretty nice?

but now for the last 2 times we have been together, I feel that she is very two faced and is putting down other of her employees and even her supervisor. I don't think I;m the only one she is confiding to however she tries to tell me that myself and another employee are in a different category, says I'm saying this not as your supervisor but as "Mary" She tells me things and tells me never never repeat it. I am becoming uncomfortable with the situation and both times I have felt bad after these incidents. I don't want to get on her bad side but I am feeling that she is really two faced but she is my supervisor.