Bad temper

The Lily of the Valley  
Blossoms beautifully
Its fragance is light and fresh
But poison runs through its veins,
A dark side  
It surely hides  
Somehow similar to this flower
Two sides are part of this girl
On her happy days,  
Like a nightingale  
Sitting on a cherry tree's branche
She sings the greatest melodies  
But when angry,
Becoming a deadly tornado  
She destroys all in her path