Master Takeshiba had been expecting this, after all, this kid didn't have any morals, and limits so what he heard was the least of what he expected.
He didn't doubt, that even if he had a mother or some grandmother that he didn't know about, this guy would come and ask to marry her to become part of the family.
And he couldn't really blame him, because this was the way that the society worked, and if one didn't have the background of a big family, then his achievements were limited.
That or he would have to totally change the society and the powers behind it. Which clearly needed a long time, and a massive amount of wealth, and strength.
What this kid might have collected until now wasn't even 0.1% of what he would need to achieve his goal, and he knew and understood that.
For that reason, he was trying to work out an easier solution, a simpler one. But he wasn't just trying to enter the high society and try for bigger achievements.