unable to pair my MacBookpro with iphone13

Correct. Direct pairing over Bluetooth is not supported.

Almost all things that require Bluetooth between a Mac and an iPhone do not require direct pairing.

What are you trying to accomplish by pairing them exactly?

Your original post mentioned nothing about Personal Hotspot.

Anyway, make sure the Hotspot feature on your iPhone 13 is turned on before you attempt to pair.

With it turned on, go to Bluetooth on the iPhone, and it should pair to the Mac. If it still doesn't work, try using Wi-Fi, instead of Bluetooth on the Mac to look for the iPhone 13, it should appear in the list of available Wi-Fi networks.

The Wi-Fi option is recommended over Bluetooth as its faster and does not rely on pairing the devices.

... when I try to pair the message...

If you are trying use Messages on your Macbook Pro, it starts with the phone.

On your phone do Settings > Messages and find "Text Message Forwarding." Your Macbook Pro should be listed; activate from the phone.

See: Forward SMS/MMS text messages from your iPhone to your Mac or iPad - Apple Support