The context of the following conversation is Sydney and Kai were best friends. Sydney wanted Kai to stay over at her house.:
Sydney says Do you want to stay over at my house?.
The friend responds I don't know,  I really need to go home and study for the big test tomorrow.
Sydney responds But we could study here! I just want to spend some times together.
The friend responds Alright, but promise that we will study.
Sydney responds I promise!.
The friend responds I'll stay over then!.