The words wrests, rests sound the same but have different meanings and spellings. Why do wrests, rests sound the same even though they are completely different words?
The answer is simple: wrests, rests are homophones of the English language.
Plural form of rest.
Third-person singular simple present indicative form of rest.
Third-person singular simple present indicative form of wrest.
Definitions 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.