Is a wife's disobedience to her mother considered an act of defiance if the mother rejected the husband but the guardian approved and urged his daughter to accept the husband? And in the event of a conflict between the husband's desire and the desire of the wife's mother, whom should the wife obey?

If the mother of the wife psychologically rejects her daughter's marriage, having initially agreed to it, then there is no sin upon the wife for disobeying her mother and accepting the marriage, as long as her guardian is pleased. The wife should strive to be dutiful to her mother and maintain ties with her sisters. If obedience to parents conflicts with obedience to the husband, then obedience to the husband takes precedence due to the greatness of his right, as indicated by the prophetic traditions and as stated by Imam Ahmad, may Allah have mercy on him. However, the wife should be dutiful to her mother as much as possible, and the husband should assist her in this.