A common sure bet is a two-way sure bet in which there's no draw outcome. An example of this would be a tennis match, a basketball game, an ice hockey game with overtime and penalties included and so on. It's easy to bet on a two-way sure bet, as you only have to bet on two outcomes between two sportsbooks.
A sure bet involves a customer betting on all the available selections for a specific betting market. In doing so, they make a profit no matter the outcome of that market, generally using a calculator. This type of betting must be done with more than one bookie and generally applies to 2-way or 3-way betting markets.