Think about cost as an economical construct. An objective means of measuring the amount of something for trade.
Likewise, think about value as a subjective and personal measurement of how important something is to you.
Trust and time are some of those currencies that people highly value.
To regain or earn back someone's trust or to make up for lost time, be it in your business dealings or personal relationships, is to understand the value that the other lost.
This can be very subjective and may have several layers to dig through. You'll need to see things from different perspectives. Sometimes this can be very costly and may require sacrifices and compromises.