一定成功的

Given the distance between my previous role as a convention gate-crasher and my newfound role as convention keynoter, I had some cause to worry that my appearance in Boston might not go very well.

我在上届大会的角色是擅闯会场者，而届大会是主要发言人，由个角色的巨大差距，我有一定的理由担心，我在的登场也许不会十分成功。