Splinter trying to redeem Big Mama is so funny
“Big Mama! Come with us! There is still good in you!”
Literally five minutes ago she was attempting to murder your children

You believed your eldest son to be dead
She was celebrating
Literally the only reason she is not actively attempting to murder your teenage sons is because her fighter turned on her
Why would you save her from him

Also you have no reason to believe in her? She kidnapped and held you captive for years and forced you to fight in the Nexus? She got you to fall in love with her, and waited until you proposed to then reveal that she’s a yokai mob boss, and then, again, kidnapped you and forced you to fight in the Nexus for years