Ah a very good question.
Eve was no more gullible than Adam. How Satan worked is to use a marketing ploy called.....network marketing through indirect distribution.
Have you wondered how companies that sell products use indirect distribution by conscripting a buyer of a product to also be a seller, within their network of family and friends.
Take for example YouTube in association with companies, who use network marketing through YouTube netsoldiers by indirectly distribute products through subscribers that cling to certain YouTube channels.
Satan initially sold the idea to Eve and used her to indirectly distribute the idea to Adam, through indirect marketing. The effectiveness of this approach, was that Satan needed to convince only one person rather than two. Notice how the drama unfolded when one tried to blame the other.....
11And he said, “Who told you that you were naked? Have you eaten from the tree that I commanded you not to eat from?”
12The man said, “The woman you put here with me—she gave me some fruit from the tree, and I ate it.”
13Then the Lord God said to the woman, “What is this you have done?”
The woman said, “The serpent deceived me, and I ate.”
Satan knew that by convincing Eve to the idea, was all that was needed and that Adam who loved Eve needed no convincing, because his guard was well and truly down.
That is why Satan is called the serpant.