And more importantly, God cannot accept this marriage.
It is written clearly in the Bible.

The reason why I am mentioning this is for the girl's concern.
If you do not convert, she will bear guilt for marrying you for the rest of her life. 
Because it is against God's will in accordance with Christian Principles.
If you really love her, you will need to consider her as a whole.

How different people interpret the Bible often tells us more about them than it does about God or the scriptures. The old barb "you can prove anything with scripture" is not entirely true, but lots of alternative and opposite opinions can find supportive texts.

I am especially bothered by those who use Bible verses to promote a God who is bent on condemning everyone to hell except Christians. And there are some who go so far as to expect God to eternally annihilate every Christian that doesn't belong to their specific denomination. That sounds more like tribalism than the religion of Jesus.

Don't get me wrong. You can make a Biblical case for such extremes. You can even promote genocide in the name of God if you cite certain verses.

But I've never understood why people would want to worship a God who was meaner than they are. That's not a God who deserves our worship. What kind of God would condemn Gandhi and the Dalai Lama to hell? Maybe an unjust, tribal deity. But that's not the God we see reflected in the life of Jesus, and it is not the God of healthy Christianity.

When Christians speak of God, we look first to the person of Jesus as the incarnation of God, the human face of God. Jesus did not run around trying to convert everyone to his religion. He reached out with compassion and understanding toward those who were outside his religion, and he treated them with love and respect.

He healed a Canaanite woman's child and the slave of an officer of the occupying Roman legions. He restored a demoniac living in a cemetery. He touched unclean lepers and a menstruating woman. He dined in the homes of tax collectors and sinners. His attitude toward those of uncertain religious virtue was remarkably tolerant, outgoing and forgiving. In fact, the only people who seemed to rile him were those who were certain of their own goodness and tried to cast everyone else in the shadow of their own rightness. He saved his harshest words for the moralists.

No wonder it was the outcast and marginalized who most embraced Jesus and his message. The people who failed to see him for who he was were mostly the Biblical literalists. Jesus didn't fit their Biblical expectations. No messiah was to arise from Galilee, they said. He broke one of the Ten Commandments when he healed on the Sabbath. He offered forgiveness freely to all instead of through the Biblically mandated Temple sacrifice monopoly. And he didn't throw out the occupying armies like the scripture promised. It was the Bible quoters who were blind to the good things he was doing. They couldn't see him as God's person because it didn't fit their Bible verses.

Too many good Christians continue to make the same tragic mistakes. They fail to see the goodness and authenticity of those outside their own circles. The fruit of the Spirit is "love, joy, peace, patience, kindness, generosity, faithfulness, gentleness, and temperance." (Galatians 5:22) Wherever such Spirit is manifest, in any culture or religion, that is the Spirit of God being manifested. Christians name that manifestation Jesus.

I see Jesus in the Dalai Lama, and, were we to meet, I would be honored if the Dalai Lama could see the Buddha-nature in me. When we follow a God who is big enough to have been revealed in many various cultural expressions, we open ourselves to the possibility of being spiritually enriched by religious pluralism rather than threatened by it.

I worship a great God who loves this creation and its creatures. God will go to any length to be in communion with us, even unto death. God is revealed in every time and in every culture, not just in mine. And I believe God intends to lose nothing of what God has made. If God can make resurrection out of the evil of Jesus' crucifixion, then God will find a way to bring blessing, healing and new life to all.

--The Rev. Lowell Grisham

This is a matter of debate within the faith communities. Each of the world’s primary faiths would claim that it is the one way to God. I prefer to think of God as one and our responses to God as partial and inevitably flawed. Each faith, then, might have a piece of the truth.

Although English Biblical translators inserted “the” into the text, in the original Greek manuscript Jesus described himself as “way,” not “the way,” suggesting that we could come to God through him, but that other ways might exist, as well. That idea is offensive to some Christians.

It seems to me that we each make our choice as to which way we will follow. What matters then isn’t that our way be absolutely correct, but that we make a sustained and faithful effort to follow our chosen path to God. Our way must withstand scrutiny – we can’t just create a faith that suits our fancy – but it need not be the way that others follow.

--Tom Ehrich