"Note: This question is not asking if we should decline, but how to do so." if this is true, then please remove all those references which are causing confusion (i.e. "We're both not sure if we should give him a chance and see how things go, ..." — goamn 1 min ago

Just to give us the full picture, have you replaced the €1.00 mixer and do you generally use each other's kitchen or other equipment? — Spagirl 1 min ago

Nice quick link: homelet.co.uk/landlord-insurance/tips/…. All a good and quick read, but the most important bit to just smoothen this great answer is under the header "Can I Take Other People Into the Property?" — Philbo 18 secs ago

Hi, just quickly for anyone looking to write an answer: homelet.co.uk/landlord-insurance/tips/… All a quick and easy read, but to summarise: legally the landlord has to give 24 hours notice and can only show people round in the last 28 days of a shorthold agreement (and it should be notice in writing, though I'm not sure if an email would count, or even a read-receipt showing time a message was received and read). — Philbo 1 min ago

I assume she knows the earth is a sphere, and you're using the term "flat earth" metaphorically. If so, NASA placed a mirror on the moon. You can aim a laser at and use to detect the reflection. There's a Big Bang episode that includes this - you can also talk about Non-Neutonian fluids (substances whose viscosity changes based on how much pressure you apply to them) which she can see touch and play with (you can make it with cornstarch and water - search for oobleck). — J. Chris Compton 1 min ago

@AmagicalFishy as a german, yes it is. If you don't bother to comply you at least clean up after yourself so no one notices. This means not only the floor but everywhere, where drops have landed. :) — Nordlys Jeger 10 secs ago

Put all the stuff on her doorstep. — Cris 31 secs ago