This melody / The Sound of Music soundtrack as a whole lives in my brain rent free. For the record, this isn't an arrangement but I freely admit to stealing the first 6 notes cause I saw the character name and then blinked and had the whole thing composed. Whoops.

Me:
https://artfight.net/~Marcato

Character is "Edelweiss" from:
https://artfight.net/~distantechoess