Yep se·rene

səˈrēn/

adjective

1.

calm, peaceful, and untroubled; tranquil.

"her eyes were closed and she looked very serene"

synonyms:calm, composed, tranquil, peaceful, untroubled, relaxed, at ease, unperturbed, unruffled, unworried;

"Peace I leave with you; My peace I give to you; not as the world gives do I give to you Do not let your heart be troubled, nor let it be fearful.