According to Oda Nobunaga's usual routine, shouldn't he bring out a concubine's younger sister for the marriage? Even if the concubine's younger sister is still young, she'd still be more suitable than Princess Gotoku.
Besides, the Oda Family is such a large clan, hardly lacking daughters. Oda Nobunaga is also quite skilled at snatching from his own kin. For example, Oichi is his cousin, whom he claimed as an adopted daughter; his eldest half-brother's daughter was also taken by him and made his own adopted daughter, with the added bonus of a good son-in-law, Niwa Nagahide.
Anyway, if Oda Nobunaga wants to find a candidate for a political marriage, it's as easy as pie. For him to marry Princess Gotoku into the Matsudaira family, he probably really likes Matsudaira Mototaka; at the very least, he holds him in high regard, right?
Maybe Oda Nobunaga sees Matsudaira Mototaka as a rare honest man?
