What is the ruling on some girls rupturing their hymen with their fingers or by any other means, or with the help of a man who inserts his finger, given their decision never to marry?

A woman's اقدام to remove the hymen is contrary to Islamic law, reason, and natural disposition, because it is a transgression against oneself and causes sadness and grief to the girl.

Marriage is among the recommended matters and traditions of the Messengers. It entails many benefits for this world and the hereafter, and it becomes obligatory for anyone who fears falling into fornication.