* Aloha: This means "hello," "love," "compassion," or "affection" in Hawaiian. It's a very versatile word and can express a wide range of emotions.
* Kou: This is the possessive form of "you" in Hawaiian, meaning "your."
While the words themselves are correct, putting them together in this way doesn't form a coherent phrase in Hawaiian.
Possible interpretations
It's possible that the phrase you heard was meant to be a different combination of words, or perhaps it's a mispronunciation.
To better understand the intended meaning, you might ask the person who said it to clarify.