A deeply felt emotion that makes your heart race, your breath come in quick gaps or ragged pants, your body tremble and your eyes shine. It is felt when a bond between two or more people is formed to such an extent that emotions are shared without a word and the bonded people are unable to be who they are without each other.
Vust is an emotion similar to "love", but much more serious and not to be said continuously or lightly.

When you eat dirt for the first time and leave your family to build a shack in the woods