Ali* had just hopped off a midnight train from Munich in Berlin's main railway station and was tired, bewildered. It was mid-September of last year, just weeks after the body of a baby refugee from Syria was found washed up on a beach in Turkey. Ali had arrived in Europe over the Balkan route: to Greece by boat from Turkey, then through Macedonia, Serbia, Hungary and Austria.

Lena* was at the station with a small group of women posted at the "Welcome Refugees" stand, and anxious with anticipation. Her friend offered Ali, 28, and his two Iraqi traveling companions a place to stay for the weekend, until Berlin's LaGeSo refugee processing center opened Monday morning.

Before the exhausted men went off with the other woman, Lena, who is 30 and studying for a PhD in political science at Berlin's Free University, jotted her name and telephone number on a scrap of cardboard, inviting Ali to call anytime he needed help.

The next day, he texted Lena to say thanks, in English. She texted back. They met with others for dinner. They texted more. They met more. One morning she brought a large bag of pastries to LaGeSo, and watched in amazement as the IT engineer from Baghdad gave most of them away to hungry refugees waiting outside the processing tents.

They knew it was love

At one point he texted that he was too busy to meet. Lena was crestfallen, wondering whether she was being overbearing. The next day Ali texted her, saying he missed her. And that was when they knew they were in love.

As heads of state are preparing for a summit on March 17 to finalize a deal to check the largest flow of refugees into Europe since World War II, in Germany the next challenge will be integrating them. Last year 1.1 million refugees arrived here.

It all started with a phone number scribbled on a piece of cardboard

The majority of asylum applications in Germany the year before were from men. And most of those were, like Ali, under 30. For integration to work, German politicians say they want to avoid creating a parallel society of Muslim immigrants living outside the mainstream of German population.

The easiest way to turn refugees into Germans might be for them to fall in love with Germans and marry them. But Ali and Lena's story suggests letting love blossom is fraught with challenges, and that it is probably only possible under very special conditions.

First night in bed with their clothes on

"My friends could all see that I was beaming when I walked into a room,” recalls Lena, who had not had a steady boyfriend for six years. "So I told them I was in love. They cautioned me against it. They said he was a Muslim, and that it was different, that you didn't know what you were getting into. They said, 'Maybe he just wants to marry you so he can stay here.'" And Lena had her own misgivings. She was afraid his tenderness was in gratitude for all the help she was giving him.

Ali had hidden out in dingy basements, negotiated deals with shady middlemen, risked his life on a crowded rubber boat,and survived his three-week odyssey on the Balkan route. But he was fully unprepared for the rituals of Western love.

He spent his first night with Lena in bed with his clothes on. "We woke up, and she wanted to kiss me, but I told her I can't,” he says. "In Iraq, we don't go out with women unless we are going to marry them.”

Five years without even a kiss

Ali had a girlfriend from the university in Baghdad for five years, and never as much as kissed her. "It's a different culture, you can't compare,” he says as he waves his hand dismissively. It took four years before he could meet his Iraqi girlfriend's parents, and then, it was only to discuss marriage.

By contrast he met Lena's parents after only four weeks, and shortly after that, he was drinking sparkling German wine and helping them trim the Christmas tree for the holidays in a city in western Germany's Ruhr Valley. Lena's family is enraptured by Ali, and sees the pair's love is real. Grandma gave them an envelope with some cash for Christmas with the words "Truth Love” scrawled in English on the front. Her father cooks with Ali; the two of them go to soccer games together.

Ali talks regularly to his father back in Baghdad, too. But it is a more guarded kind of speech. He cannot tell him about Lena. "Before we get married, I will tell him, then everything will be good,” he explains.

He says all refugees from the Middle East he knows believe German women are unclean, because society here does not prohibit sexual activities before marriage. His father and family in Baghdad share that view. Not Ali: "To me, what matters is that I know the girl, and that I trust her. That's all."

Ali spends each morning at a software company that is helping him re-enter the IT business, and afternoons he goes to language courses.

'Every refugee should have a German girlfriend'

He says having such a schedule is a challenge to someone used to spending a lot of time on his own, and then, of course, Lena has her own expectations. "But look, I am easy,” he quips. "She says do this, and I do it.” Lena says every refugee should have a German girlfriend, to help them get things done.

"I come from a privileged background,” says Lena. "I know that. My father is a surgeon, and my mother is a physician. We had a house in Miami. I lived for a while in New Zealand. I fully expected I would marry someone from a similar background. I never imagined I would fall in love with someone like Ali."

Then came the bag of pastries in the LaGeSo processing center.

*Names changed by request, to protect families involved.