Unfortunately, the lack of trust goes hand in hand with the withholding of important information (including the internal conversations around willingness and capacity.)

Without trust people wont’ open up fully, won’t renegotiate powerfully and the silence is often misinterpreted as buy-in leading to future and costly breakdowns. This book lays the foundation for commitment-based management. Thanks for the review and reminder of such pertinent information.

Our first advice when someone is resisting to make weekly commitments is to ask what they can commit to. What are they working on now and what can they commit to have done end of tomorrow or even end of today. It can help to discuss how making commitments gives a person more power to say “No” to some of those requests that pop up.
There is also a common mis-perception that commitments are written in stone. In fact, a principle of managing with commitments is that commitments are negotiable. There should be no stigma attached to speaking up as soon as a commitment seems to be in jeopardy and negotiating a modified commitment in alignment with the team’s goals. This sometimes needs to be over-communicated, especially when people feel they were unfairly treated in the past (could have happened in another org or before you got there). Obviously, a habit of renegotiation commitments all the time is not very productive, but our experience is when people start managing commits, they get better at meeting them.
Peer pressure is also helpful especially in getting started managing commitments. It is a lot harder for one person to say it is impossible to operate from commitments, when their colleagues are making and meeting commitments in their regular team meetings.
Other thoughts?

How can we encourage team members to be completely open and communicate exactly what their assessment is, with everyone aligned around the shared purpose of the final goal.