Hi guys!
SPOILER! If u want to find out still how to this quest DO NOT READ IT!
First to unlock dalia, u have to do his quests.
I just leve it here.
https://grimdawn.gamepedia.com/Missing_Diary
https://grimdawn.gamepedia.com/A_Sister's_Love
https://grimdawn.gamepedia.com/Family_Matters
Mothers Pendant
U have 2 choice here: 1. U can give her the pendant in mourndale if u do whole quest line or…
Hope it helps boys. 
Attachment: screenshot47.jpg