What is the ruling on a woman who broke her fast for 40 days in Ramadan due to an excuse and did not make them up, and how can she remove doubt and please Allah Almighty?

You must fast the current Ramadan, then make up the forty missed days, along with expiation for each day by feeding a poor person (one mudd of wheat or half a sa' of other staple food). This expiation is for delaying the make-up fast until after the subsequent Ramadan. Hasten to make up the fast after Eid al-Fitr.