Is it permissible for a Muslim woman to befriend a non-Muslim woman if the latter is modest and well-mannered, without neglecting her own religion, and is there a severe punishment for doing so?

A Muslim woman's companionship with a disbeliever is harmful to her religion, which is why the Prophet, peace and blessings be upon him, said: "Do not accompany anyone except a believer." This complete companionship does not mean a complete boycott, so it is permissible to visit them and give them gifts with the intention of inviting them to Islam, and the Prophet, peace and blessings be upon him, and his companions did this. However, visiting a disbeliever merely for companionship is not permissible, though accepting their gifts is permissible, and congratulating them on their holidays is not permissible.