* Fear: He's terrified that the ladies will report him for having books. The firemen are supposed to be the only ones who have books, and he knows he could be in serious trouble.
* Guilt: He feels guilty for betraying his profession and for having books in the first place. He's not sure he can handle the consequences of his actions.
* Hope: He's holding onto a sliver of hope that maybe, just maybe, there's something good about books and he should be able to keep them. He's starting to question the world around him, and the books are his only source of different information.
Ultimately, Montag's decision to hide the books is a turning point in the story. It shows that he's starting to rebel against the society that has been forced upon him, and that he's willing to take risks for something he believes in.