In the whole Boruto story, from the movie to the anime and the manga, one of the most important characters is Sarada Uchiha; she’s Sasuke and Sakura’s daughter and also the only chance for the Uchiha clan to survive. In addiction, she stated that she wants to become Hokage, so that she’s supposed to be the character who’ll continue Naruto’s will to take care of Konoha and his friends.
Yet from the first episodes, she demonstrated to be very clever like her mother but also very skilled in fighting like his father and that’s the perfect combination which will make her an incredible strong kunoichi.
Furthermore, Sarada developed her Sharingan at the age of 11 years old, thanks to the strong emotion felt for having seen her father after many years; with her one-tomoe Sharingan she has been able to adjust her abilities, becoming even more skilled in hand-to-hand combat. Then she has also been able to develop her Dojutsu, gaining the two-tomoe form of her Sharingan during the Chunin Exams; this evolution allowed her to start using the first genjutsu, which are very powerful techniques developed in particular by Uchiha clan members such as, for example, Itachi and Shisui.
Since now we have always be convinced that the Sharingan (and also the Mangekyo form) could have been awakened only through strong negative emotions, but guess what? Sarada’s emotion which made her Sharingan awakening was everything except negative, so that in order to develop a Mangekyo Sharingan she probably could feel not a negative emotion, but an even more positive one, a proper “trauma”!
Thinking about this, what could be this emotion?
Well, my theory is the one which follows: we all know that Sasuke has never had Itachi’s or Shisui’s ability in genjutsu, although he developed an Infinite Mangekyo Sharingan; but, on the other hand, he also owns Rinnegan, and we know that the Rinnegan is a combination between Sharingan and Byakungan, so that thanks to that eye also a non-Uchiha clan member could eventually use Uchihas Genjutsu.
Now, in my opinion there will be a particular situation at a certain point in the anime in which Sasuke will need Sarada to become stronger and, for this reason, he will cause in her mind the trauma she needs to awake her Mangekyo Sharingan; since he loves her and he doesn’t want her to live some bad experience, I think Sasuke will affect Sarada with a powerful genjutsu made thanks to his Rinnegan and, while under the illusion effects, Sarada will meet her uncle Itachi, talk to him and see his particular relation with his elder brother and how he sacrificed himself in order to defend Konha.
This incredible event will probably awake Sarada’s Mangekyo Sharingan, since she would become aware of something she had never imagined, probably also becoming capable of evoking her Susano’o and use more powerful genjutsu, for example like her uncle Itachi’s ones.
Of course this is only a theory, but in my opinion Itachi is one of the most loved Naruto characters ever and it would be really strange if no one shows him again, also just in a memory; furthermore Sarada’s is the daughter of one of the strongest shinobi ever, so that she can’t be supposed not to awake the Mangekyo Sharingan and keep just her three-tomoe “normal” Sharingan.