It is, as I believe, the holy spirit. It isn`t from knowledge, it isn`t from reasoning with anything, but in the rare case, its when you KNOW you can be apart of it, something you don`t want to let go, and isn`t a THING to let go with. Its just the knowing that you want to hold on, that is in trust, that stems only from you, through you. As one might say, love is as a sigh, as the holy spirit, is just a breath away.