PG / PG-13
Firstly I love this movie and it's witty, charming and cute without coming on sappy.
There are many movies like this that I think the MPAA is clueless about. To merit a PG-13 rating by definition is supposed to contain some content they may want their child under 12 not see without the proper context. Titanic truly is a PG-13 movie by having a semi-graphic nude scene (albeit brief), coarse language including a couple f-words and usually violence isn't an issue which is so backwards.
Besides being held at gunpoint and Tai's drug references are the only PG-13-ish the movie contains.
I would rate it PG for some sexual content and some language
A person hates you because they either wanna be you, see you as a threat, or hate themself