I wouldn't take a check. They may not be sincere. 2 things I've done when guests owed me:
I would offer go to a cash machine with them in a friendly way, or even a supermarket where you buy some small pricey things quickly and they pay. Then I just kept things smiley and friendly but persistent.
This assumes they agree to the amount. You can offer top give them a receipt.
Almost everyone has either paypal, Venmo, or access to Quickpay/Zelle through their bank. It's easy enough if they have their bank's app on their phone. You can do this research quickly now to see if you are set up to receive payments this way.
Please let us know what happens! And remember that it's our job as hosts top warn others. That's another topic but they might be motivated top handle this the right way. If you do give them a so-so or worse review, careful to be factual and objective in your tone.