It is not unusual for trailers to have slightly different takes than the final version of the movie or even to include moments that do not actually appear in the movie at all.  Trailers are prepared before the movie is completed.  And there are often amendments in the trailer to make movie’s edgier material acceptable for general audiences. This trailer has all of the above:

A couple of these moments are not in the film and the figure on that apron worn by Jason Segal is not wearing underpants in the movie.

But the television commercial for “The Five Year Engagement” has one other curious change.  In the version I have here, the little girl says, “I’m Pocahontas!” before shooting the crossbow.  On the television commercial version, she says, “I’m Katniss!”  Of course it makes more sense for a little girl to know the American History legend and star of a Disney movie than the lead in a series of books for teenagers and a movie rated PG-13.  But for some reason, the marketing geniuses behind this film thought it would sell more tickets to insert a timely “Hunger Games” reference into the commercial despite the fact that it is not in the movie and does not really make any sense.