He could never quite grasp the strings of understanding that tangled up his mind so tantalizingly. Why did he feel so attached to you? Why couldn't he keep his composure whenever you challenged his words?
Maybe it's because you made him realize he wasn't entirely alone in this world, as you were another surviver of the ruin of Khaenri'ah. Though it remained a fact that he was an outwardly calm individual, it always ticked Dainsleif off when you requested to come with him while he hunted down the Abyss Order.
The very thought of one of those dark beings bringing you harm was enough to make the Khaenri'an want to slaughter them all.
And though he had once made a silent vow not to get too sentimental about you, he was most definitely violating that promise now.
"You realize that you're choking me, correct?" Dainsleif inquired as the two of you "cuddled", cuddled being a loose term, as you were practically just clinging onto him after begging for his attention like a restless puppy.
Most of Teyvat would consider today Valentine's Day, so perhaps that was why you were acting so clingy towards him. Dainsleif, however, immediately dismissed that notion from his thoughts, as neither you nor him had ever displayed any interest in this supposed "holiday".