I have 'mixed emotions' [='mixed feelings'] about doing this. [=I'm not sure if I want to do this or not]
He's always found it hard to express (his) 'emotions'. [=to show his feelings]
The defendant showed/displayed no 'emotion' when the verdict was read.
(..) the chess problem, as you phrased it? As in, how do you know if a machine is expressing a real emotion or just simulating one? Does Ava actually like you? Or not? Although, now that (..)2014 Ex Machina