Notes: We don't know who the SUBJECT is in the first sentence. However, this subject should be a MALE, because of the way "idiot" is written in Japanese. (This is said in a "playful" way, and the suffix "-kun" suggests it was said by a woman to a man.) An alternative translation would be: ... is my little idiot! PS: This first sentence is not natural in Japanese (in the same way as this is not a common ENGLISH expression). --- The "you" in the second sentence is usually used when a man is speaking to a WOMAN.