How to spell SERENTIY correctly?

If you meant "serenity", here are a few correct suggestions: serenity, sereniti, serenitea, serenityu, serenitysue.

• serenely She sat on the dock, gazing out at the serene lake, breathing deeply and feeling serenely calm.
• serenity I crave the serenity of the countryside to escape the chaos of the city.
• seventy I have to study seventy pages of notes for my final exam.

Attenttion

• attention
• attentions
• attenuation
• inattention