Sentence:  Only the memory of previous hurt , bewilderment and perplexity made him sure that if he did not ask B ' dikkat when he , Mercer , <WSD>was</WSD> happy , the answer would no longer be available when he needed it . 
Meaning of the word marked with <WSD> tags:  have the quality of being; (copula, used with an adjective or a predicate noun)