Watch-only wallets are wallets on Trust Wallet that only allow you to view funds/token balances but won't allow you to transfer or swap them for other coins since you don't have access to the passphrase of the wallet. To withdraw from a watch-only wallet, you have to get the 12-word passphrase for the wallet and import the wallet into the Trust Wallet. After doing that, you should be able to withdraw funds from the wallet to your bank account using the guide above.