The National Enquirer is a tabloid and has a reputation for printing anything without confirming its authenticity. The subject matter of the letters does not paint the victim in a positive light and seem to be fabricated, especially since they were not original letters, but copies. Sandy Arias claimed the originals were destroyed.
If they were genuine, then they would have been entered in as evidence in the Jodi Arias trial or a more reputable news source would have agreed to publish them.
Mike Walker did tell Nancy Grace that he felt one of the letters was silly. He was referring to the letter about Travis Alexander wanting Arias to wear his cuff links so he could see his initials while she performed oral sex on him. The editor said that it seems like a woman would write that sort of thing, not a man.
When Nancy Grace asked Mike Walker if the National Enquirer was going to publish the letters, he said that a decision had not been made yet and they want to be very careful because of the ongoing trial.
The letters also say that the victim admits to hitting Jodi Arias in the face and that marrying her would erase the deviant thoughts he had about her. It seems that the killer is scheming even while she is behind bars. It is no secret that Jodi wanted Travis to marry her, but she would not make a suitable Mormon wife and she was simply his "dirty little secret." Perhaps Arias' narcissism wants to prove to the world how desirable she is, which is common in those with narcissistic traits and would explain why she would fabricate the letters and include the marriage bit in them.
There is also the question of why these letters are surfacing now instead of when she was arrested. The only reasonable explanation is that Jodi knows that she is going to be found guilty of Travis Alexander's murder. Her mother, Sandy Arias, is working with her daughter to somehow prove to the public that the killer was a defenseless "victim" that was abused.
Are you disgusted by these alleged letters that Jodi Arias' mother is selling the tabloids?