Arcana Coelestia # 3100
3100. 'The man, wondering at her, remained silent' means a state of perception regarding those things. This is clear from the meaning of 'wondering but remaining silent' - when he saw that the things he had spoken in his heart were actually taking place - as a state of acknowledgement, yet at the same time of waiting to see whether it really was so. He 'wondered' because he acknowledged that things were happening as he had prayed, but he 'remained silent' because he was waiting to see whether it was in fact so. This is the state of perception that is meant.
Heart
The heart means love. A good heart means love to the Lord and to the neighbor, while a hard or stony heart means the love of self or the world -- riches and things. When the psalmist asks the Lord to search his heart, he wants the Lord to see what it is that he loves. And we are what we love. What we eat may form our earthly body, but it's only temporary, what we love forms our spiritual body, beautiful or ugly as we have chosen. It's interesting to note that the first multi-cellular motion of our embryo is the pulsating that starts in a twist of blood vessel that is to become our heart, and the last motion of our natural body is our heartbeat. It is there for all of our natural life. And of course there is a beating heart in our spiritual bodies when we come to put them on.