promising

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

a promising young apprentice

The obtained low and anisotropic thermal conductivity, and feasibility of synthesis, in addition to other reports on high electron mobility, make arsenene a promising material for a variety of applications, including thermal management and thermoelectric devices..

Encouraging and inspiring confidence.

The act of making a promise.

So it cannot be supposed that promisings differ from other word-givings in that a word-giver makes a promise only if he or she uses the locution "I promise".