I'm not an expert so someone please correct me if I'm wrong but I'd look at everything. If K-S suggests data is not normal and trimmed mean suggests it is, I'd be looking at the other information you have, what are skewness and kurtosis like? What about your histograms and Q-plots? Did you get a normality plot with your histogram? How well does it fit? As far as I understand, you need to be able to justify your stats so as long as you have a logic and viable reason, you should be fine. I hope that makes sense... and good luck!