I could really do with some advice on this one.. I've had au pairs before and it's always worked out brilliantly with the ones who want to get stuck in with family life, explore London, experience a new culture and improve their English.
So I tend to select my au pairs on how enthusiastic they seem about spending a year with us and how they get on with the kids, rather than how domesticated they are. I have relaxed expectations on that front and am rarely disappointed, ha ha 
A new 18yo au pair joined us from France last weekend. She came from an agency and I chose her as she seemed to tick all of the 'enthusiastic' boxes on interview - Skype, a couple of telephone calls and my lovely former French au pair talking to her too.
So I was quite surprised when we got to the 'no boys in your bedroom' conversation to be told that she is engaged to be married. Her and her fiancé are childhood sweethearts and had every intention of going to a FE college together. He flunked his Baccalaureate and needs to spend a year retaking, which is why she is now au-pairing.
We're less than a week in and she is clearly miserable and the opposite of enthusiastic about being here. She didn't tell either me or my former au pair she was engaged, nor did we ask for that matter. I'm also pretty straight down the line about no men I don't know/haven't met in the house overnight, even if they are engaged to my au pair - I'm a single parent. This may become an issue in future.
Has anyone ever had an experience like this before? I expected an enthusiastic teenager, not a homesick fiancée...my instinct is that this may not be a passing phase either, but on the other hand we're only one week in.