It's possible that:
* There's a misspelling: Perhaps you meant "La Chère" which means "the dear one" or "the beloved one."
* It's a proper noun: "La Shae" could be a name, possibly of a person or a place.
* It's a dialectal or regional term: Some words are specific to a particular region or dialect of French.
Could you provide more context? What was the situation where you encountered this word?