I don't get how the sentiments work either because my sim child is also still peeved at her mother for not "blessing her" and it's been several in-game weeks now (the reason why she wasn't blessed was because I couldn't figure out how it worked), it's quite annoying tbh.
Edit: She is now peeved at her TODDLER brother for not blessing her at the Festival of Youth, like beech what? He's your brother and a toddler, why tf should he "bless" you with "youth" when he's a youth himself and when he WASN'T EVEN AT THE FESTIVAL? Gosh darn it, I hope they tweak the sentiments because they are annoying af.