A young socialite trying to escape her controlling and abusive fiance falls in love with a penniless artist on board Titanic.

OK, thanks.

That's why it's posted in the "Classics" repository.

A good deal of insight can often be gleaned by examining and trying to improve upon loglines for popular movies, especially those that don't follow the traditional Hollywood story structure (hero's journey/protag with a specifically-defined goal) and as such don't lend themselves as well to standard logline structure (ie. American Beauty).

Just for the record, the IMDb logline for Titanic:

A seventeen-year-old aristocrat, expecting to be married to a rich claimant by her mother, falls in love with a kind but poor artist aboard the luxurious, ill-fated R.M.S. ~ Titanic.

Hasn't James Cameron already made this movie?