Okay, so often times, anything to do with the characters being prositutes ends up having a tragic story flow. This one isn't any different... At first. ;P
Well, come on, the story DOES need to develop first right? It won't be so smooth-flowing for both of them for some time, but stay on it.
Currently, the scanslation is at volume 2, and how they left it hanging will truly pull on your hearstrings and make you feel depressed, what with the situation of the two protagonists and Kaname Itsuki sensei's drawing- where the emotions are very well expressed on their facial expressions, too well in fact, that you might somewhat be influenced by the emotions of the character at present.
However, fear not. Since this is based on the novel, Hanafurirou, I can assure you that it WILL have a happy ending.
A warning though, for those who are not too fond of romance/angst genre, it would be better for you to wait until all (assumingly, if it follows the novel length) 8 volumes are scanslated.
This has a lot of angst- even with the mood lightener you still won't be able to get the depressing thought induced by the previous pages.
Even so, this is truly a great read.