Like Tadaakira, Yasuto was very generous about bribery and accepted a bribe of 6,000 ryo from Sakyo SENGOKU, hitto karo (the head of chief retainers) of the Sengoku clan of Izushi Domain in Tajima Province; in consequence, he married a daughter of his brother Chikara MATSUDAIRA, a branch family of hatamoto yoriaiseki (a family rank of high-ranking hatamoto) off to Sakyo's son, Kotaro SENGOKU, which later led to his downfall.
忠成同様、賄賂には大変鷹揚なところがあり、但馬国出石藩仙石氏の筆頭家老の仙石左京から6,000両もの賄賂を受け取り、その結果、実弟の分家旗本寄合席・松平主税の娘を左京の息子仙石小太郎に嫁がせたが、これがのちに康任失脚の布石となってしまう。