If by any reason, you were scammed but already made your Bitcoin transaction to a trade partner, you lost your bitcoin almost forever, except if you can file scam report to police for help. You can do it or can not do it, and it depends on legality status of Bitcoin and trades via bitcoin in your country.
Just like if you are buying the house with fiat or local currency. But people will follow lefal procedures to acquire a house, making sure it is not scam. I see this just like fiat scam.
Depends on value of your trade, assuming buying a house is a big trade, you must have enough confirmations.
What's the rule of thumb for an acceptable number of confirmations?
- 1 confirmation: sufficient for small payments less than $1,000.
- 3 confirmations: for payments $1,000 - $10,000. Most exchanges require 3 confirmations for deposits.
- 6 confirmations: good for large payments between $10,000 - $1,000,000. Six is standard for most transactions to be considered secure.
- 10 confirmations: suggested for large payments greater than $1,000,000.
If you do not want any reorganization attack to occur (but which is not possible as bitcoin Network is right now), you need to wait for 56 confirmations. The reorganization risk is 0% starting from 55 confirmations.
But the way bitcoin network is right now, there is no problem with having just 2 confirmations.