Assumption is a type of Acquisition. Acquisition is related to Buy. you would Buy because Better. Repair is a type of Better. 
Achievement is related to Level. Level is a type of Destroy. Destroy is the opposite of Rebuild. 
Assumption --IsA--> Acquisition <--RelatedTo--> Buy --MotivatedByGoal--> Better <--IsA-- Repair 
Achievement <--RelatedTo--> Level --IsA--> Destroy <--Antonym--> Rebuild 