A beginning can be tentative while the decision behind it remains serious.

A quiet start and a weak commitment look similar from outside and are not the same thing. Someone can be entirely certain and still begin carefully, because early steps are where you find out what you did not know. Loud confidence is a style rather than evidence, and demanding it of yourself at the outset mostly delays the start. Seriousness lives in whether you continue, not in how you announce.

If you are waiting to feel sure before beginning, allow yourself a small and unimpressive first move instead. Tell one person what you are doing, and keep the scale modest enough that the second step is easy.