But if you do not trust me…—If you say to keep his fangs to himself.Astarion lo

But if you do not trust me…

—
If you say to keep his fangs to himself.

Astarion looks so hurt, wounded almost. The way he hides his eyes not finding strength to look at you.
And the next moment he speaks about trust. That gives all the new hue to his inner struggle. It seems that under all his sass he hides the fact that MC is the first person in a long time, whom he was counting as… friend at least. Someone he can trust. And now he feels betrayed.

Also, he looks the same in the biting scene, when you internally accuse him of being a vampire and a slave to the hunger. As if he’s hating that side of himself. And it’s getting in the way again, but this time he has had no fang hand in the situation.