How to understand that adults should be responsible for their words and deeds? How to understand the word "responsible"?

You have to honor your promise and do what you said, which is to be responsible for what you said. What you have done has caused bad consequences, and you have to bear the consequences. You are responsible for what you have done. Being responsible means being a responsible person, being responsible for your words and deeds, regardless of the consequences, and considering the feelings of others.