The sentence seems open ended enough that it could be anything. If that's where your mind goes .. well. You can say it's implied or obvious, but you can only know for sure if you asked the person that translated it to this what their intent was.

I'd just read the sentence as something else if the implication bothered me that much. "I wonder, what's the color of the hair like when seen under a moonlit sky? Her beauty must melt a man's heart then, surely!"

He's not finishing the sentence. Your mind is filling in what he was going to say, based on your own expectations.