yeah, trying to get someone into horror but having to try and fit that criteria could be very tricky.
you could maybe try a cross-genre movie to start her off, to peak her interest maybe? perhaps
shaun of the dead? (although it gets pretty gory.)
or maybe try something that is heavy on the scares but low on gore, with relatively quick pacing, along the lines of
amityville horror or
the omen, (i would like to say the originals, but she might like the remakes more), or even
the exorcist, maybe?
or maybe neverending is right. she might just not be destined to be a horror fan. if she finds the classics boring, doesn't like gore, and has a short attention span, then it seems like she is lacking in the some of the fundamental qualities we horror fans all share.
anyway, you'll probably have to just tie her up and force her to watch: