The words paced, paste sound the same but have different meanings and spellings. Why do paced, paste sound the same even though they are completely different words?
The answer is simple: paced, paste are homophones of the English language.
Simple past tense and past participle of pace.
A soft, smooth, thick mixture or material, as:
A smooth viscous mixture, as of flour and water or of starch and water, that is used as an adhesive for joining light materials, such as paper and cloth.
The moist clay or clay mixture used in making porcelain or pottery. Also called pâte.
A smooth dough of water, flour, and butter or other shortening, used in making pastry.
Definitions from Wiktionary, Creative Commons Attribution/Share-Alike License, 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.