Sigh is related to Night. Night is related to Dress. 
Dancing can cause/lead to Fatigue. Stress can cause/lead to Fatigue. Stress can cause/lead to Headache. Headache is a synonym of Bother. 
Sigh <--RelatedTo--> Night <--RelatedTo--> Dress 
Dancing --Causes--> Fatigue <--Causes-- Stress --Causes--> Headache <--Synonym--> Bother 