There is definitely a difference between verbal agreement and written agreement. Verbal agreements don’t seem very solid, and can be manipulated if there isn’t proof of the agreement. Written agreements seem a bit more trusting, since there is physical proof, and you know for a fact that this can’t be manipulated by the other party because its already documented. I don’t think its a good idea to start a project based on a verbal agreement, because again, if this agreement was not documented it can easily be manipulated. And if that was to happen, a lot of time spent on the project would be going to waste. Therefore, if your making an agreement to start a project I think its best to make sure it is documented.