Well. I have never done a trade here, but on another forum I frequent, it usually is based on feedback.
For example, since you have zero feedback, and just registered, most people won't ship first or even deal with you. You would need to offer to ship first. That would alleviate some of the worries from the buyer.
There is no guarantee anyone will ship you anything. That's just the whole risk with doing any transaction online. But if the person you're dealing with is an established member here (or can provide feedback from another forum and validate it), there is no reason to suspect you will run into any problems.
As for the keyboard. It's really up to you. Trading might be harder, so maybe just offer to sell it. I don't know what the price is worth but I'm sure someone else could help you out with that.