Denshi Jisho — Online Japanese dictionary

必ず かならず always; without exception; necessarily; certainly; without fail; positively; invariably
Common word, Adverb 
必ず かならずや certainly; surely; definitely
Adverb 
必ずしも かならずしも (not) always; (not) necessarily; (not) all; (not) entirely
Common word, Adverb 

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