Pay is related to Buy. Buy is a type of Believe. Believe is related to Belief. Conviction is a type of Belief. 
you would Relax because Rest. Vacation can be used for Relax. Vacation is a type of Spend. 
Pay <--RelatedTo--> Buy --IsA--> Believe <--RelatedTo--> Belief <--IsA-- Conviction 
Rest <--MotivatedByGoal-- Relax <--UsedFor-- Vacation --IsA--> Spend 