Comparative form of serene: more serene(adjective)
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Use "serener" in a sentence
"Genevieve, on the contrary, was serener than ever, though fluttering most alarmingly within."
"They brought back to his thoughts the early death – bed he had seen her tending, and the love the child had borne her; and on the wings of such remembrances she seemed to rise up, far above his idle fancies, into clearer and serener air."
"This was the beginning of a serener season for the chastened spirit of Baptista Heddegan."