Wow, rarely came across such a good sketch draw. The detail-level is magnificant high, the shades giving the whole picture a living touche. the poste of the two people just says "Love", alongside with the rose it is an perfect example. They look natural, her hair is very nice done.
Try to lighten the background a bit so the focus returns to the main characters. Also, use lighter and more strokes for his hair, so it looks more fitting to hers.
Overall it's a stunning piece of art that is worthing nothing less then fours stars, but the impact - the story of love, expressed through a simple pose - is what really makes this picture magnificent.
This picture... All the details. Their faces, the wrinkles on his sleeve, a small strings of her hair... I've never seen anything like this before. Even though it's not in color, it shows many emotions, their feelings for each other, their closeness. You have a great feel for human's body size, as well as a great feel for shading their faces.
This picture is so simple, and yet... So effective, so strong. It's almost as I can feel the smell of that flower.
But, on the other hand, I do have some things that I don't like/understand:
1. The surface under his right arm. Is it his sweater, or? 2. His hair is somehow a bit too shiny. It looks like a anime character hairstyle. I mean, it's too much brighter than hers and too... Spiky. Maybe you should have done it in the same technique as you did with her hair?
My conclusion: a great piece of art, honestly. But, as always, there is room for improvement, so keep that pencil in your hand and draw a lot more