In Debate, the principle of charity is to provide favorable interpretation of what someone has written or said that it is consistent with the evidence.

interpret opposing views honestly and in their strongest form.

An example on principle of utmost good faith is diverting some of your income towards charity.

The principle is important to have and act upon because we were made to have different views and opinions on life issues, choices, and decisions. We were not all made to think alike. I could not imagine living in a world were there was no friendly debates.

The idea is we must assume he is using our own logic when making his statements or else we cannot understand what he is saying at all.