Found 2 synonyms
quietly, coolly, serenely, peacefully, softly, gently, tranquilly, smoothly, composedly, still, evenly, mildly.
More calmly synonyms
placidly, very quietly, leisurely, with equanimity, at ease, serene, undisturbed, untroubled, unruffled, peaceful, imperturbable, unperturbed, unmoved, nonchalant, impassive, coldly, patiently, easily,
Synonyms "calmly" in the picture