How did it end?

After quite a while he returns to see Iris. She is on her way home from grocery shopping and he stops next to her with his new car. I figure that it was more than a year after he left, because when he asked her whether she had received all his letters she mentioned 15 letters, one get-well-card (spelling?), one for easter and two for valentines day. Anyway, she gets in the car and while driving her home, he proposes to her. He tells her about that house he found in Detroit and that he would like her and the kids to live there with him. She asks him if he is really willing to take the whole family with him and he just answers: "Iris, I'm here." When they arrive at her house, she already starts talking about changing stuff in the house and when they enter the house the credits start to roll in. So, it's a happy ending.

Hope my english was good enough to help you and you got the picture. But you should really watch it for yourself sometime, it's a beautiful ending to a beautiful movie. One of my favourites.