Must do a few Alchemy quest's first given from "Seiri" the General goods vendor in Duvencrune, then after the Alchemy quest's you should get & accept "Seiri's dilemma" quest, Talk to Kubo for "Duvencrune Observation Log 1" Knowledge, Then Talk to Maopan for "Duvencrune Observation Log 2 Knowledge" Then Talk to Rinta for "Duvencrune Observation Log 3" Knowledge, go back to Seiri & Accept "Advice for Seiri" after that, Accept "Lack of Courage"
go back to Kudo to get "Seiri's Past 1" Knowledge, go back to Maopan to get "Seiri's Past 2" Knowledge, go back to Rinta to get "Story of the Big mouth" Knowledge.