The Fool (spoilers for all RotE books, including LST)

[Valarya]

It is ignorance of human nature to believe anyone could become a lover of a best friend who mislead you to believe they were a different gender while also acknowledging that they are in love with you. People would feel betrayed. They would not trust that person because they carried on a lie. They would never have a chance to know the "real/true" person because they would slam up walls of distrust, resentment, repulsion even. Repulsion, because of the betrayal as well as the incompatible sexual orientation. (Fitz was clearly heterosexual). Who could be attracted to someone they had always thought of as the gender opposite of their own? Even if that friend looked beautiful/handsome as their true gender it would not matter. To suddenly find out that the person you thought you knew enough to consider a trusted close friend was in fact a female posing as a male would end most friendships instantly. You could not feel you knew that person. You could never see them the same way. They would be someone else. You would not have a chance to develop a friendship with that new person. The ingredients for friendship would be lacking. Most people would walk, if not storm, away from that friendship and not want to look back.

I just wanted to interject that most of the people on this forum feel exactly the same way about why a Fitz/Fool relationship could never work.

I felt the need to clarify that Farseer is only telling you what a large majority of other fans 'wanted' from the ending - and how they reacted.