Caoimhe, Josie, Ife and JJ.
I didn't like what they were saying and I strongly disagreed with their accusations and suspicions.
I think Corin genuinely is "that nice" all the time, and yes, she is human so will have an off day now and then, or shout at someone if she feels the situation requires that course of action.
It is silly of Josie and the others to think she is fake, just because she briefly lost her temper on one occasion after finding all her personal stuff moved around.