My view is that they are both Human and probably doing what they think is the right thing; we all live on the same planet so we need to cooperate and live in peace, that is the right thing.
I imagined it would be more difficult to cooperate and be in harmony if we met aliens from another planet. Everything we say and do could be misinterpreted as a threatening gesture.
We could look at the face of and alien and smile at them but a smile may not have a meaning to them because they can't smile so it is just a movement that makes no sense in their view. Perhaps you could give them flowers and they would think that you are giving them dead plants so you are warning them that you will use violence. Even a hand shake or a wave could be seen as a threat. Or perhaps the aliens get in your space and growl at you as way of showing respect and peace not knowing that humans would see that as a threat.
They may think that our maps are upside down. They may see the south pole as the top of the planet and see everything differently. Different views can cause mistrust.
They would not trust us, we would not trust them. The only way they would trust us is if we were both telepathic; in my view music gives us simple telepathy because our mind set is similar when we listen to music, but that is not enough. We would need true telepathy.