Promises are just a good way to get gullible people to do what you want, Pinkie Promises especially so.

If Pinkie heard somebody say this, how would she react?

Something akin to this, probably:

Y-You... really think that? B-but... *Gallops away crying*

Now you're gonna pay, PAL.

Least that's how my versions would react.

“Well, I guess I can see where you’re coming from. But that’s really not the point at all. A promise can be so much more than that. It’s a great way to communicate intentions, and keep each other accountable. I’m sure I can help you understand my point of view. I’ll do my very best.
I…
promise…”