Breakdown of Как мило с твоей стороны!
твой
your [informal]
как
how
сторона
side
мило
sweet, nice; it is sweet
Questions & Answers about Как мило с твоей стороны!
The current lesson is about Что за, so why do we use Как here instead?
Что за translates to "What a..." and is followed by a noun in the Nominative case, like Что за милый человек! (What a sweet person!). Because мило is an adverb here, we must use Как (How). This is the standard way to make exclamations with adverbs or short adjectives.
Why is с твоей стороны used here instead of just saying от тебя?
С твоей стороны literally translates to "from your side." It is a fixed idiom in Russian used exactly like "of you" or "on your part" in English. While от тебя means "from you," using it in this context sounds unnatural, as if you are physically receiving a physical object from the person.
What case is твоей стороны in, and why?
It is in the Genitive case. The preposition с takes the Genitive case when it means "from" an abstract direction. Because сторона (side) is a feminine noun, its Genitive form is стороны, and the feminine modifier твоя (your) becomes твоей.
Could I use the full adjective милый or милая in this sentence instead of мило?