It's not that Gu Heng wasn't being cautious, but over the past few days, Bai Qiusheng had made her extremely tense. So, she could no longer tell when Bai Qiusheng was telling the truth or lying. He simply told her, "Everything will be settled in a few days. When that time comes, you will be the female lead."
By this point, Gu Heng had long given up on the idea of being female lead. All she was worried about now, was whether Bai Qiusheng would be exposed.
However, Bai Qiusheng didn't share any information with her. He simply told her to wait and to make sure not to reveal their relationship. But, this cluelessness was the reason that she took Bei Chendong's bait as soon as he threw it out - because she had no idea what Bai Qiusheng had planned.
In the middle of the night, Gu Heng left her home without her assistant. All alone, she drove to her usual meeting place with Bai Qiusheng; an underground cafe.