there a movie about dilapidated hotel with marisa tomei and Robert downey jr called majestic?

You're close! There *is* a movie about a dilapidated hotel starring Robert Downey Jr. and Marisa Tomei, but it's called "Only You" (1994).

"The Majestic" (2001) is a movie starring Jim Carrey, not Robert Downey Jr., about a screenwriter who loses his memory and ends up in a small town where he becomes the unlikely hero.

It's easy to mix them up, as both films feature a small town setting and a focus on a character with a troubled past.