The Lord watches from heaven; he sees all people.
From the place where he lives he looks carefully at all the earth’s inhabitants.
He is the one who forms every human heart, and takes note of all their actions.
As a fan of Lord of the Rings, I can’t help but think of the evil eye of Mordor that represented Sauron. He could see across the land and had great power. Of course Sauron was a better depiction of the Devil than of God. In fact, that character was in fact very limited in its scope and power. From what I have studied about the Devil (which I admit isn’t all that much), he can observe our actions but he doesn’t know our hearts or thoughts like God does.
In fact, God doesn’t just know our hearts. He formed them himself. Nobody knows us better than the one that created us from nothing.
So the bottom line here is that you can’t fool God. You can’t hide from him. You can’t convince him that you are something that you are not. So you might as well be open and honest with him from the start.
You also can trust God. You know that he loves you in spite of any and all bad things you’ve ever done. He knows about all the times you’ve lied, cheated, and hurt other people. He knows and yet he still loves you.
He doesn’t condone any of this behavior, but if you accept him as Lord and Savior, he wipes the slate clean and considers you sinless. What an amazing gift.