You can always trust the Blockchain to give you an accurate result, use a Blockchain explorer like Blockchair to monitor your transactions and only pay when you have received at least 3 confirmations.
Using block explorers is never safe. For starters they are the enemy of your privacy since they record your activity and link it to your IP and possibly your identity. Additionally many of them have bugs that could be exploited if you are checking validity of a transaction or its confirmation.
You should stick to a trusted wallet that directly connects to the bitcoin network either as a full node or an SPV client connecting to a full node.