Very confused?!? Spoilers(of course)

The woman at the beginning of the movie is Hella who also gave birth at the end of the movie. My guess is that she ran away from that place after she found the black hole. She knew the meaning of it after all the research she did. She was not a sacrifice because they only needed a sacrifice once in 7 years. She was pregnant and scared, so she run leaving a box with her research behind to warn others. The father at the end was Maries trainer.
A lot of loose ends in the movie though...
Why would Dirk call Marie over to the clubhouse to see some old newspapers if he could just take them with him instead of waiting in the lair of the enemy (and bringing Marie there also)?
Why would Bobby keep those newspapers around waiting to be found bij anyone?
How could 'the gild' kill two cops and another man outside such a large building without being seen?
there are a lot more of those questions...

But the midwife called her Hella. "What are you going to name her, Hella?" Surely that is not a coincidence.

I know I'm late to this discussion. I want to add my conclusion and this link to a page I just put up showing Marie is born to Hella and the coach, and that the midwife/nurse is Bobby's Grandmother.

http://imalreadytoobusy4this.blogspot.com/2016/02/left-bank-linkerover-2008.html

I don't like spoon-fed horror. So I've watched this thing 4 or 5 times now.

Bobby definitely loved Marie. That's why he made the ultimate "love sacrifice" and sent her through the hole to the alternate universe where she could start a life at the beginning again, because he believes that she will be happier. We see how much he loves her throughout the film. He tells her she is the first person he has ever given flowers to, he tells her she doesn't look happy even when she is running. He tells her he thinks he knows how to make her happy. The grandmother excitedly tells her how he's talked about her and when he says we're trying to take her mind off running, the grandmother says to her everything will be better soon. And Marie tells Bobby lots of things like how she wants to start again, and life isn't right.

The neighbor lady, when giving Marie the info about Hella, said she didn't want to call Dirk the boyfriend herself because she got a bad feeling from him. He does drag her in further, and even tells her to come to the Guild which is obviously "unsafe" just to show her something. He also drags her mother in, and her mother gets killed. He hits on her when he sees her in Hella's skirt. There's a creepy element to Dirk, which is good because it re-casts Bobby in the good light he's supposed to be in.

Time isn't linear. It's not like Marie was reborn in the future, or on a timeline. Things are layered and parallel sometimes. She went through the hole into an alternate universe to start again.

It's possible there was a subplot that Hella disappeared by Dirk's hand, but that's on the editing room floor. We know it's Hella in the beginning of the film finding the hole in the basement because its her same sticky note that is on the box of Hella's stuff in the apartment. We know it's Hella at the end because the midwife calls her Hella and that's just too coincidental. But we don't really know what happened to her in the first world. Her being pregnant and giving birth in the parallel world doesn't necessarily mean anything. Did she fall into the hole? Or is that another her? We don't know.

I do think the hole passes into another universe, another dimension. I do not think it is just a time portal, because that would be linear and limited to only the same timeline in past present future, and that doesn't work here. I don't think Hella happened to hook up with the coach in the present linear time line and Marie was reborn to them. Although neither the coach or Hella have aged at all, Bobby's grandmother is there too. Also, when the camera pans out the window after you see all the potted sunflowers inside, you see the outside. It's the Left Bank, and it looks different, with fields of sunflowers outside.

I think the Dragon Guild that makes the sacrifice every 7 years, is sending someone to be reborn in the alternate universe, which is right there parallel to theirs. It's the healthier, happier universe. I think that's why the grandmother says to Marie it is a sacrifice of love, because Bobby loves her so much he is sacrificing his own happiness by sending her away. He does it for her happiness, to give her a new start.

I liked the movie. There's a lot of unanswered questions, and there is a lot of symbolism, like the mouse. The silt Marie has inside of her shows she is selected for rebirth. And there are also storylines that don't pan all the way out enough to connect without creative thinking. Like, the absentee father, and the idea that Marie has to get sick so she can't go away to run. When she runs again anyway, she hurts her knee. She is being kept from leaving, so she'll be here for the sacrifice. But what there was of a storyline really worked on a lot of levels.

Someone on another thread remarked at how hot the sex scene was between Bobby and Marie when they first met. That is very true and very intentional. You see his scars, and you see how they connect. She was the right one.