That depends on you and all your particulars. One can be easier than the other and vice-versa depending on many factors.
Marketing and Selling are like opposite sides of the coin, like heads and tails, they are one and the same but they are also opposites.
Certain people are more like Marketing people than Sales people as some people are more Sales people than Marketing people, I can't really tell any more than that.
Both do have the same goal, making money. And both are needed to do just that.