Who is Taylor swifts song i knew you were trouble about?

Taylor swift's song "I Knew You Were Trouble" is widely speculated to be about her relationship with American actor Jake Gyllenhaal. The song's lyrics paint a picture of a whirlwind romance that quickly turns sour, describing a man who is charming and exciting at first but ultimately proves to be untrustworthy and problematic. While Swift has never explicitly confirmed the song's inspiration, multiple details in the lyrics seem to allude to her brief but intense relationship with Gyllenhaal in the fall of 2010, which ended reportedly due to Gyllenhaal's commitment issues.