Here are some sentences.
Goodness knows why you cannot do your own work.
If you had any goodness in you, you would not cheat.
In general, "goodness" does not require a capital letter unless it starts a sentence or is used as part of a proper noun or title.
oh my goodness?
This gift certificate is presented to you in recognition of your all-around goodness.
the enjoyment of the amazing goodness of people is amazing
He is Epitome of Goodness
Thank goodness someone asked that question. Tom's goodness is a sharp contrast to his wife's hateful character.
Goodness is a quality that represents kindness, compassion, and positive actions towards others.
He is the epitome of goodness
My goodness, this is a rather tawdry scene!
I can give you several sentences."Surely goodness and mercy shall follow you all the days of your life." (from the Bible)Goodness knows how you got that crazy idea!Her goodness makes everyone love her.
She baked a batch of cookies for the charity event to spread goodness in her community.
Goodness generally means the state or characteristic of being good. It is generally that which is healthy, valuable or beneficial. An example of a sentence with goodness in it is "That candy bar was filled with creamy goodness." It also can be used to express shock or surprise, as in "Oh my goodness!"