unfaltering
From Longman Dictionary of Contemporary Englishunfalteringun‧fal‧ter‧ing /ʌnˈfɔːltərɪŋ $ -ˈfɒːl-/ adjective formal DETERMINEDstrong, determined, and not becoming weaker unfaltering confidenceExamples from the Corpusunfaltering• unfaltering loyalty• Press, and out comes an unfaltering milky flow.