Paying with a cashiers check? Need advice!

So I have a deal set up for a new to me pre here on Audiogon. The issue is the seller only wants to excepts a certified bank check. I have never paid this way before and I am a bit nervous. He says all the right things almost to much honestly. He does on the other hand have fifty some positive reviews and I talked to him on the phone as well. Which is when I got a bit more suspicious after he offered me a deal on a disk player at below half market value. He seems genuinely nice but I’m sure the best scammers do. Is there any way to get extra insurance that everything is legit? And would you guys be ok with it being he has 50 positive reviews over nearly 20 year span?  Looking forward to people thought. And thanks.