On an app
She has not answered for four days, and the conversation had been going well.
The line for this moment
I'm guessing you're busy or it's not a fit. That's completely fine. All the best to you.
Safein the pack
The Vietnamese for it, how it sounds to an English speaker, why it works here and not elsewhere, and what she is likely to say back with what to do next: that is what the pack opens, for this line and the others like it.