In the movie, after a Fremen named Jamis challenges Paul to a trial by combat, Chani gives Paul a Crysknife (the one he saw in his prescient visions). Although she fully expects him to lose, the gift is an act of kindness, as wielding it in battle will allow him to die with honour. In the book, however, Chani gives Paul detailed guidance to help him win the faceoff instead. Thus, the nature of their interaction in the movie is more nuanced.