I'm a Muslim woman living in Sweden and I draw Henna for Muslim women here, there is a Muslim sister who wants me to draw her henna on her wedding day and for her female friends too, the problem is that some of her friends are not Muslims and I'm afraid if they "the non-Muslims" will use the drawings on their bodies to show their beauty for men. So I want to know if it is "Halal" to draw Henna for non-Muslim ladies or not?

In shari'ah (Islamic law), this is permissible. This is because if something can be used for either purpose [lawful and prohibited], it is then permissible to deal with it whether by manufacturing, selling or buying. The sin lies only upon the person who uses it in unlawful ways.