How can one reconcile the desire to develop one's English language skills through "Facebook" and communicate with the opposite sex, especially with a non-Muslim Croatian man, while upholding religious principles, and is it advisable to invite him to Islam?

A woman is permitted to invite a man to Islam, provided she adheres to the Sharia's guidelines and etiquette. It should be noted that the general principle is for men to invite men. A man can be directed to English Islamic websites such as Islamweb and Sheikh Ahmed Deedat's website. Furthermore, a woman must sever her relationship with any non-mahram man to avoid the temptation that Satan might exploit.