To convince or persuade one to do something or to accept some plane or idea. Often used in passive constructions. I can't believe he sold me on another one of his harebrained schemes. I just don't like the way their customer service agents try to sell you on extra policies or more expensive packages—that's the sales team's job. I wasn't sold on the idea until they showed me exactly how they planned to spend the money.

Totally confident in or convinced of someone's or something's viability, veracity, appropriateness, skill, etc. I don't know, this plan still sounds pretty risky to me—I'm not sold on it yet. After seeing the presentation, I'm sold on this investment—let's go for it! A: "What do you think about the new quarterback?" B: "He's someone who's supposed to be the best in the league, but I'm not sold on him yet."