One man is renting apartment to one girl, he is spying on her, from the mirror in the bathroom and rape her and in the end she finds out that he was spying on her.

Do you by any chance know the movie tittle?

This is a bit of a guess:

The Resident (2011)
starring Hilary Swank (http://www.imdb.com/name/nm0005476/?ref_=tt_ov_st), Jeffrey Dean Morgan (http://www.imdb.com/name/nm0604747/?ref_=tt_ov_st), Lee Pace (http://www.imdb.com/name/nm1195855/?ref_=tt_ov_st)
IMDb synopsis:
In New York, Dr. Juliet Bliss Devereau of the Brooklyn General Hospital has ended her relationship with her boyfriend Jack and is seeking an apartment in Brooklyn to live alone. She finds a bargain in an old apartment building owned by the handsome and lonely Max and one night she misinterprets his signals and dates him. However she concludes that it is too soon to have a love affair and she asks Max to leave her apartment. However she does not know that Max is a deranged man obsessed on her and that he spies her from secret openings in her apartment. Further, Max is drugging Juliet every night and sexually abusing her. Juliet has troubles to wake up in the morning to go to the hospital and decides to install a monitoring system in her apartment. She learns the truth about Max but how will she escape from the insane landlord?

The Resident (2011) - IMDb (http://www.imdb.com/title/tt1334102/)