It happens. Whatever occurs in life, inside you knew it was going to happen.
How do you know that 2 + 2 = 4? What does it feel like to know that? It feels like nothing because when you know something, you do not need to struggle with it. There is no need for an inner dialogue on the subject. If you are asking a question about it, then you are not certain about it.
We are constantly transmitting what will occur next to the universe based on what we know will happen. The universe then presents it to us in a physical form that we call life. When you question if something will occur, you introduce possibility which may or may not work in your favor depending on what you know the odds are.
Life is simple.