I've referenced this before, but it's worth posting again. Here is link to Kirsten Power's testimony of her conversion to Christianity. Her testimony became Christianity Today magazine’s most-read Web story in 2013. Read it in entirety. Here's an extract ...
Of all people surprised that I became an evangelical Christian, I'm the most surprised.
In fact, the week before I met him, a friend had asked me if I had any deal breakers in dating. My response: "Just nobody who is religious."
A few months into our relationship, my boyfriend called to say he had something important to talk to me about. I remember exactly where I was sitting in my West Village apartment when he said, "Do you believe Jesus is your Savior?" My stomach sank. I started to panic. Oh no, was my first thought. He's crazy.
... I had found this man's church attendance an oddity to overlook, not a point in his favor.
As he talked, I grew conflicted. On the one hand, I was creeped out. On the other hand, I had enormous respect for him. He is smart, educated, and intellectually curious. I remember thinking, What if this is true, and I'm not even willing to consider it?
... We were meeting in an auditorium with a band playing what I later learned was "praise music." I thought, How am I going to tell him I can never come back?
But then the pastor preached. I was fascinated. I had never heard a pastor talk about the things he did. Tim Keller's sermon was intellectually rigorous, weaving in art and history and philosophy. I decided to come back to hear him again.
... Each week, Keller made the case for Christianity. He also made the case against atheism and agnosticism. He expertly exposed the intellectual weaknesses of a purely secular worldview. I came to realize that even if Christianity wasn't the real thing, neither was atheism.
I began to read the Bible. My boyfriend would pray with me for God to reveal himself to me. After about eight months of going to hear Keller, I concluded that the weight of evidence was on the side of Christianity.
... I suddenly felt God everywhere and it was terrifying. More important, it was unwelcome. It felt like an invasion. I started to fear I was going crazy.
I didn't know what to do, so I spoke with writer Eric Metaxas, whom I had met through my boyfriend and who had talked with me quite a bit about God. "You need to be in a Bible study," he said. "And Kathy Keller's Bible study is the one you need to be in." I didn't like the sound of that, but I was desperate. My whole world was imploding. How was I going to tell my family or friends about what had happened? Nobody would understand. I didn't understand. (It says a lot about the family in which I grew up that one of my most pressing concerns was that Christians would try to turn me into a Republican.)
I remember walking into the Bible study. I had a knot in my stomach. In my mind, only weirdoes and zealots went to Bible studies. I don't remember what was said that day. All I know is that when I left, everything had changed. I'll never forget standing outside that apartment on the Upper East Side and saying to myself, "It's true. It's completely true." The world looked entirely different, like a veil had been lifted off it. I had not an iota of doubt. I was filled with indescribable joy.