Nmadu disclosed that the singer believed in the biblical injunction that marriage is for better for worse.
She said the deceased endured the troubled marriage believing that her husband, Peter Nwachukwu will change.
Mrs Nmadu made the revelation while speaking with members of the Nigeria Association of Women Journalists in Abia State.
She also claimed that Nwachukwu deceived the family that he was a pastor when he wanted to marry Osinachi.
She said: “Osinachi believed in the biblical injunction that say marriage is for better for worse, and that was why she endured the marriage thinking that Peter Nwachukwu will change but unfortunately, my daughter died”.
Mrs Nmadu also disclosed that the children are now with one of her daughters.
She urged the NAWOJ to help her get justice.
Osinachi’s death has been linked to Nwachukwu.
Despite the outcry, Nwachukwu had denied being responsible for his wife’s death.