Complex sentence: Though they initially interact well, Starr correctly deduces that Astrid is having an affair with her live-in boyfriend and, after a loud argument with him, She storms into Astrid's room in a blind and jealous rage and shoots her.
Split into simpler sentences: Though they initially interact well, Starr begins to suspect that Astrid is having an affair with her live-in boyfriend, which turns out to be true. Eventually, after a loud argument with her boyfriend, Starr enters Astrid's room in a blind and jealous rage and shoots her.