There's lots of excellent advice in this thread: https://pinside.com/pinball/forum/topic/how-to-not-get-ripped-off-in-pinball-vids-guide
Basically, if you don't have an existing relationship with the buyer and cannot get cash, wire transfer is the safest way to go, but you'll need to confirm that it made it to your bank (and as described in the thread above, that it was an actual wire transfer). For big dollar transactions or if you want extra certainty, escrow may be worth the additional cost (see thread above).
If you decide to accept a personal check/cashier's check/money order, you should build in four weeks for the check to clear before you ship the game. Don't be mislead by "funds available within 48 hours," you want the check/MO to truly clear so the money isn't sucked out of your account again later if it bounces. (again, details in the thread above, but research clearance time as maybe you'd want to allow longer for a Canadian check to truly clear).
