A cashier's check is a type of payment instrument issued by a bank, guaranteeing the funds are available. It is created when a customer requests a check and provides the bank with the necessary amount, which the bank then holds in its own funds. This makes cashier's checks a secure form of payment, often used for large transactions like real estate purchases. Unlike personal checks, which can bounce if there are insufficient funds, a cashier's check is backed by the bank's own money. This reliability makes it a preferred option for transactions where the seller wants assurance of payment, such as in real estate or vehicle sales.