Unknown is related to Uncertainty. Uncertainty is a different concept from Sure. Sure is related to Promise. Promise is etymologically related to Commit. 
Find is a synonym of Regain. Regain is a synonym of Recover. Recover is a synonym of Heal. Heal is related to Part. 
Unknown <--RelatedTo--> Uncertainty <--DistinctFrom--> Sure <--RelatedTo--> Promise --EtymologicallyRelatedTo--> Commit 
Find <--Synonym--> Regain <--Synonym--> Recover <--Synonym--> Heal <--RelatedTo--> Part 