He was this close to get laid or what?
Not really... He was already full well aware of what she was after, and he wouldn't have taken the bait.
Even as a "no-strings-attached Seed Donor" she'd be tied to his Guild and dragon sanctuary, because MC is not the type to father a child in the Fire-and-Forget style.
And he is very much not inclined to let
anyone close to his dragon sanctuary, and as a result himself, unless he knows he can implicitly trust that person.
Which the lady in question isn't even close to earning...
In that sense MC's devotion to his dragons is a pure Plotanium chastity harness..
The arrival of the noble simply was a nice author excuse to not have to write our MC yeeting her out of the door with some Excuse which might have been constructed as Rudeness.