I used to feel that Connie didn't know what happened to Fredo.

But taking into account her statement about Fredo's death in context with what Michael has just told her - that he has confessed his sins to the Cardinal - this would imply that she DID at some point realize what happened and over the years has accepted and forgiven Michael.

"I love you Michael. I'll always help you."

Apple

A wise and frugal government, which shall leave men free to regulate their own pursuits of industry and improvement, and shall not take from the mouth of labor the bread it has earned - this is the sum of good government.

- THOMAS JEFFERSON