Sentence:  And when belief was dead and God a myth, / And the world seemed a wandering mote of evil, / <WSD>Endurable</WSD> only by its impermanence, / And all the planets perishable urns / Of perishable ashes, to you alone I clung / Amid the unspeakable loneliness of the universe. 
Meaning of the word marked with <WSD> tags:  Able to be endured; tolerable; bearable.