The words fairs, fares sound the same but have different meanings and spellings. Why do fairs, fares sound the same even though they are completely different words?
The answer is simple: fairs, fares are homophones of the English language.
Of pleasing appearance, especially because of a pure or fresh quality; comely.
Light in color, especially blond: fair hair.
Of light complexion: fair skin.
Free of clouds or storms; clear and sunny: fair skies.
To get along: How are you faring with your project?
To go or happen: How does it fare with you?
To travel; go.
To dine; eat.
Definitions from The American Heritage® Dictionary of the English Language, 4th Edition and Wordnik.
Homophones (literally "same sound") are usually defined as words that share the same pronunciation, regardless of how they are spelled.