The reason your cat sleeps next to you may be because it feels safe and comfortable. Cats generally enjoy human company, especially when they are tired or want to rest. So if your cat likes to sleep next to you, it's probably because she sees you as a reliable companion and feels safer and more relaxed around you.
There are other reasons why your cat likes to sleep next to you. For example, your cat may choose to sleep next to you to protect you, or because she likes warm places and the heat of your body can bring warmth to her. Regardless of the reason, though, if your cat likes to sleep next to you, it may be a way of showing her trust and affection for you.