What is the ruling regarding a woman who deliberately misses three days of Ramadan fasting without a valid excuse, and what is incumbent upon her?

The questioner broke her fast for three days in Ramadan out of negligence, committing a great sin by violating the sanctity of Ramadan which Allah has enjoined.

She must make up for these three days. If her husband had intercourse with her on one of those days when she was not fasting, in addition to making up the day, she must offer the expiation for intercourse (freeing a slave; if she cannot find one, then fasting for two consecutive months; if she cannot do that, then feeding sixty needy persons). If the intercourse occurred more than once, the expiation is required for each instance.

She must also offer sincere repentance and seek forgiveness, and resolve not to break her fast in the future. Additionally, she must feed one needy person for each day she delayed making up the fast until after the subsequent Ramadan.