When you send USDT on the BNB Smart Chain network, the transfer is recorded as an event on a public ledger. Verifying a deposit means reading that ledger and checking several things at once.
The transaction must exist and have succeeded. It must be a transfer of the correct token contract — not a look-alike token with the same name. It must have arrived at the correct address. The amount must be decoded using the token’s own decimals. And it must have accumulated enough network confirmations to be considered settled.
Only when all of those hold is a deposit treated as confirmed. A transaction ID on its own proves nothing, which is why it is checked against the chain rather than taken at face value.