Source : Webster's Revised Unabridged Dictionary (1913)

Serenely \Se*rene"ly\, adv.
   1. In a serene manner; clearly.

            Now setting Ph[oe]bus shone serenely bright. --Pope.

   2. With unruffled temper; coolly; calmly. --Prior.

Source : WordNet®

serenely
     adv : in a peacefully serene manner; "I had the feeling that he
           was waiting, too--serenely patient"