Questions: Guy's Behavior

I suddenly realised my one night stand (I never intended it to be that way), works at the place my sister went to the other night. She embarrassed herself big time and had a complete meltdown, screaming and shouting, out of anger. I’m not like this but I feel that guys will think she’s me so I can never be my own person and always carry my head in shame due to her behaviour like this. So we look very similar and have almost identical sounding voices, but you could tell which one is which by looking at us. My question is would my one night stand, he spent the whole day with me, think that she’s me? Would he remember my voice alone and think it’s therefore me or are voices hard to remember? Also if we only look very similar but not identical would he think that was me. Please be honest thanks