Person does not want (to) Mortality. Person is related to Sister. 
Overwhelming is a form of Overwhelm. Overwhelm is a synonym of Overcome. Overcome is a synonym of Own. Own is a synonym of Confess. 
Mortality <--NotDesires-- Person <--RelatedTo--> Sister 
Overwhelming --FormOf--> Overwhelm <--Synonym--> Overcome <--Synonym--> Own <--Synonym--> Confess 