can yall recommned me some mangas where it is sad at the begining and the ending is very g...

First one that comes to mind would definitely be If you hate me so.
Some others that might fit imo would be:
Sayonara Alpha
Good day to go crazy
Boku o Warui Ko ni Shite
Kurui Naku No Wa Boku No Ban
Hina wa Mitsuiro no Koi ni Torawareru (sad in middle)

thanks (づ￣ ³￣)づ