bought into

[Tinkerbell]

Instead, she took a deep breath and said, “I fell in love with a vampire. I let her turn me because I bought into?? that whole eternal love spiel. Then The Eye staked her, and I . . . I killed someone because I was starving. Eventually the Council took me in and sent me to Hecate.”
benefit?

[emsr2d2]

Instead, she took a deep breath and said, “I fell in love with a vampire. I let her turn me because I bought into?? that whole eternal love spiel. Then The Eye staked her, and I . . . I killed someone because I was starving. Eventually the Council took me in and sent me to Hecate.”
benefit?

"To buy into" means to believe that something is true, sometimes without requiring any proof or evidence.

I totally bought into that "Macs are better than ordinary PCs" idea, but now I realise it was just hype!

My cousin totally bought into Scientology - we had to rescue him from the cult after a couple of years and now he's in therapy.