Date is related to Boyfriend. Boyfriend is a synonym of Fellow. Fellow is related to Buddy. 
Difficulty is related to Easy. Easy is the opposite of Complex. Complex is a synonym of Involved. 
Date <--RelatedTo--> Boyfriend <--Synonym--> Fellow <--RelatedTo--> Buddy 
Difficulty <--RelatedTo--> Easy <--Antonym--> Complex <--Synonym--> Involved 