The words find, fined sound the same but have different meanings and spellings. Why do find, fined sound the same even though they are completely different words?
The answer is simple: find, fined are homophones of the English language.
To come upon, often by accident; meet with.
To come upon or discover by searching or making an effort: found the leak in the pipe.
To discover or ascertain through observation, experience, or study: found a solution; find the product of two numbers; found that it didn't really matter.
To perceive to be, after experience or consideration: found the gadget surprisingly useful; found the book entertaining.
Simple past tense and past participle of fine.
Definitions from The American Heritage® Dictionary of the English Language, 4th Edition, from Wiktionary, Creative Commons Attribution/Share-Alike License and Wordnik.
Homophones (literally "same sound") are usually defined as words that share the same pronunciation, regardless of how they are spelled.
If they are spelled the same then they are also homographs (and homonyms); if they are spelled differently then they are also heterographs (literally "different writing").