At You Own Risk - Scenes like this are a trope in cinema, and the story always goes the same way: friend warns protagonist, protagonist does not take that seriously, in the end protagonist discovers the love of his life, and coincides with what the friend had told him.

Note 1: As Will says He who warns is not a traitor, he is a warner

Note 2: Now that I know the future, I can change it! Mwahahahahaha!