He knew in his heart what had to be done.

I know in my heart probably what the real reason was.

The god has said so, and I know it in my heart.

But, I know in my heart this is not so.

He knew it in his heart and put the idea away from him.

I think every most senior knew in her heart what she would say when the time came.

But she knew in her heart that he would not live until morning.

I know it in my heart; ask me not how or why.

You know in your heart that there is no hope for us.

"I know in my heart that nothing like this will ever happen again."