Simple:
* She lay blissfully unaware of the storm raging outside.
Descriptive:
* The aroma of freshly baked bread filled the kitchen, making her blissfully forget about her worries.
Figurative:
* The children ran blissfully through the field, their laughter echoing like a symphony of joy.
Formal:
* The couple exchanged vows, blissfully unaware of the challenges that lay ahead.
Humorous:
* He was blissfully ignorant of the fact that his pants were on backwards.
The best sentence for you will depend on the context and the overall tone you want to achieve.