I've been Catholic from birth. My religion has taught me to show the other cheek. I am getting to know a Muslim girl 'better', even in the sense of possibly converting and marrying her, so I would like to know whether I can apply the same principles? Or does converting to Islam mean I have to apply the Jewish principles of 'an-eye-for-an-eye'?

All perfect praise be to Allaah, The Lord of the Worlds. I testify that there is none worthy of worship except Allaah, and that Muhammad is His slave and Messenger.

First of all, we supplicate Allaah to guide you to Islam.

Know that tolerance and kindness are more in Islam than they are in Christianity. Islam is the religion of mercy, truth, honesty and fulfillment of promises and pledges. It is not a religion of murder, terror and horror as presented by its enemies. In fact, embracing Islam and marrying a good Muslim girl really helps you practicing noble character, mercy, pardon, and forgiving those who hurt you more than what Catholics can teach you. If you embrace Islam and study its fundamentals and principles, you will conclude that it is the best religion and the most merciful to all creatures.

For more benefit on the religion of Islam, please refer to Fatwa 81979, and for the prophecies given by Jesus about Muhammad please refer to Fatwa 81396, and to Fatwa 83990 about 'Muhammad in the Bible'.

As for the reality of Jesus please refer to Fatwa 88187.

We aslo encourage you to carefully read the translation of the meaning of the Quran, being just and impartial as you ponder over its teachings. If you do so, you will certainly conclude that this Quran descended from Allaah, and that Muhammad , is truly His last Prophet. 

Allaah Knows best.