Don't be shy drop the saddest/most tragic manga/manhwa/mahua you've read. it doesn't matter if it's bl/gl/sl your girl just wants to feel pain
Boy meets Maria
And maybe these 2
http://www.mangago.zone/read-manga/diamond_dust/
http://www.mangago.zone/read-manga/can_t_see_can_t_hear_but_love/
same author as sweet trap, never understand and incorrigible??? oh this boutta be GOOD