Here's why:
* "Usted" is the formal "you" in Spanish.
* "Esmi" is not a word in Spanish. It seems like a combination of "es" (is) and "mi" (my) which would be "es mi" (is my).
* "Señor" means "Sir" or "Mr.".
Possible corrections:
* "Usted es mi señor." (This is grammatically correct and means "You are my master" or "You are my lord".)
* "Usted es mi amo." (This is also correct and means "You are my master".)
The best way to say it would depend on the context and the intended meaning.
Let me know if you have any other questions!