1. be confident or assured of an outcome
you can count on me/it
If you 'count on' someone or something you rely on it and trust it."You can count on this car, it never breaks down." If you say 'you can count on me' you are assuring the other person you are capable and reliable for the task at hand. "I will make sure the delivery gets there on time, you can count on me." If you say 'you can count on it' you are confident of an outcome. "It will rain later today, you can count on it." These are all popular phrases you will hear in social and business contexts.