Sentence:  The appointment of U Thant of Burma as the U.N.'s Acting Secretary General - at this writing , the choice appears to <WSD>be</WSD> certain - offers further proof that in politics it is more important to have no influential enemies than to have influential friends . 
Meaning of the word marked with <WSD> tags:  have the quality of being; (copula, used with an adjective or a predicate noun)