And while giving these big promises he doesn't think once about the consequences he might have to face in the future. When he promised Pakhi to always keep her in his heart, did he not even once think that she will actually believe it and turn psycho later on. Didn't he think that one day he will have to get married and how can he still be in love with his brother's wife then.
Coming to Shruti, in his mind once the truth is revealed Sai and family will fall at his feet and beg forgiveness. But he can't take back his promise made to her and his name on the birth certificate, so why doesn't he think that in the future she can legally claim her rights from him. Which will be a bigger issue for Sai and him.
If not foresight he could be least use some common sense before opening his mouth.