This isn't about expecting a favor in return. Sierra Summers did this partly for her brother and partly because she really needed her help.
That's what friendship is about, helping each other out.
Sierra Summers also hoped Celeste Yates wouldn't always belittle herself.
She didn't want Celeste Yates to be overly grateful and polite because of this help, and become distant in the future.
Moreover, Celeste Yates's personality is gentle and meek, like water, so Sierra Summers felt it would take time.
As expected, as soon as Celeste Yates heard she was needed, she immediately agreed, "When?"
Sierra Summers replied with a smile, "This Friday afternoon, I'll ask my brother to pick us up then."
Celeste Yates didn't react to the word "brother," nodding normally, "Okay, I'll get the things ready first."
She immediately started moving.
