I read the first chapters and was curious, you see I had actually enjoyed "good ending", but then I looked into Domestic girlfriend and to throw such a curve ball at the very end means you can't be trusted, that sort of attitude is Rian Jonhson levels of subversions, it means at any point if the author feels like it a mugger could show up and shoot one of the girls who dies...except she gets in a Coma and then wakes up after 50 chapters to have amnesia and then fake it......I am making it up but this is the sort of drama I feel.
You can't just establish certain things and distrupt them, if you give an audience X character you can't decide after so many chapters that it was actually Y all along, you sold me X, not Y.
Bottom line is, look at Domestic Girlfriend
Ask yourself, "can I trust the author of this?" If the answer is yes, then you may read this Manga.