Responses
http://www.mangago.zone/read-manga/let_dai/ Its really good, and will definitely make you cry. Its not happy ending, but I don't know if I would consider the ending sad though.
Boys Love
The reason i don't read tragedy tag anymore (￣∇￣")
Guys please recommend me some sad ending manga (if possible) and contains tragedy, angst, or else that can make me cry my eyes out. So far I already read Life Senjou no Bokura, Paradise View, Ikuse no Toki o Koete, Lonely to Organdy, Ashita Shinu, Hana no Miyako de, Torikago Syndrome, Kosha Ura No Natsu, Kashikomarimashita Destiny... and I forgot what else.