Though Konrad treated his harem members with incomparable care, the premise was that they were his. Never did he show such attention toward a wholly unrelated woman with nothing to do with him. If they didn't know him better, Verena and Selene would have believed his display to be a show of compassion.
And when even they couldn't comprehend what went on, one could only imagine how startled the girl was. And in that situation, she spoke the only word she could think of:
"W..why?"
Indeed, if someone appeared out of nowhere to rescue you from damnation and promise the world, the first question was "why?" And having never experienced any form of warmth in her life, the girl just couldn't wrap her head around Konrad's move.
"Because such is my wish. Your innate talent may not be anything extraordinary, but your heart is the most suitable for inheriting my craft. In time, I believe you shall be one of the sharpest spears by my side."