From UBC Wiki

what are sufficient conditions? a condition A is said to be sufficient for a condition B if and only if the truth/occurrence of A guarantees or brings about the truth/occurrence of B

Examples: Having four sides of equal length, where each side forms a 90 degree angle with the other side, is sufficient (and also necessary) for being a square.

Getting on a bus from Vancouver to Whistler that is running to schedule (because there are no delays), and that continues to run to schedule until it reaches Whistler, is a sufficient condition for arriving in Whistler on time.