How long does a USDT transfer take? On TRON it usually lands within minutes, while on Ethereum the time follows congestion and the fee paid; no network keeps a fixed schedule. Part of every wait is confirmations. Blockchain confirmations are the count of blocks from the one holding a transaction up to the newest: the block that includes it is the first, and each later block adds one. More blocks make a reversal harder, so the receiving platform waits for its own number, often between one and six for bitcoin, before crediting the balance.
How to convert BNB to USDT depends on where the BNB sits. On an exchange, a convert or trade screen sells BNB for USDT and shows the price and fee before confirming. From a wallet the owner controls, a decentralised exchange performs the swap on chain, with the network fee paid in BNB, and the price filled can differ from the quote through slippage. The USDT contract address should match the one published by official sources, because a name and symbol are easy to copy. Keeping a little BNB back pays for later fees.
How to sell USDT for cash usually follows one of two routes. On a regulated exchange, the seller deposits USDT on a network its deposit page lists, sells on the market and withdraws the money to a bank account, after reading the fees and withdrawal limits. Selling to another person through the marketplace of an exchange keeps the coins in escrow until the seller releases them. A seller releases nothing before the money shows in the bank account itself, since screenshots of payments are easy to fake, and payments from third parties can get a bank account frozen.