Ritz (˶˃ᆺ˂˶)

Hi I want to find this manhwa I read a long time ago, I don't remember a lot but I can say it was kinda one of those reincarnation romances, the FL tries to befriend the villain when they're children and even gives him a necklace(?) But he throws it in a lake, and then he becomes kinda obsessed with her when they are older, I'm sorry for giving a vague description but if you remember any that are like that pls let me know ╥﹏╥

it's about a girl who finds out that her classmate has a son, her classmate is a boy and the son it's like, a 4yo or something, if someone knows the name i will be eternally grateful ฅ^•ﻌ•^ฅ