Is it permissible to marry a Christian girl who will embrace Islam later, and will a person be rewarded for this if he strives to teach her, or is it better to marry someone of the same faith?

It is permissible to marry a Christian woman, and you will be rewarded for your intention to bring her into Islam. However, it is preferable to marry a Muslim woman who is religious and of good character. One should be cautious about being lenient in conversations with girls over the internet, and not rush into marriage. It is advisable to consult parents and experienced individuals, perform istikhara (prayer for guidance), and get to know the girl through trustworthy people.