promising

To commit to (some action or outcome), or to assure (a person) of such commitment; to make an oath or vow.

"He promised to never return to this town again."

To give grounds for expectation, especially of something good.

"The clouds promise rain."

The act of making a promise.

Showing promise, and likely to develop in a desirable fashion.

"a promising young apprentice"

Encouraging and inspiring confidence.