When it comes to religion, faith and belief are often used interchangeably. While they are similar to each other, there are also some differences between the two. Basically, faith is a strong devotion to something or someone, while belief is the mental state in which trust is placed in someone or something without any proof. At a glance, they do seem to be the same thing, but let's take a look at what these differences really mean.
Faith is a belief in something without any proof, usually in a spiritual or religious context. For example, you might have faith in God even though there is no concrete proof that He exists. However, there is more to it than simply believing that something exists without evidence. Faith is all about devotion. Not only might you have faith that God exists, but you are utterly devoted to Him and the effect He has on your life. No matter what happens, that devotion does not change. You believe that things will work out according to God's will.
You can also have faith in another person. For example, maybe a friend will offer to help you in a time of need. You can't predict the future, so you won't know for sure that your friend will help you, but you simply have faith in your friend. You're devoted to your friendship, and what it means, so you know in your heart that they will come through, even though they technically haven't yet.
Belief is a feeling that something is true. That may sound similar to faith, but there are some differences, the biggest of which is devotion. You can believe that something exists without having the devotion that comes from having faith. Let's go back to the example of the friend who said that they would help you in your time of need. You can believe that they will help you based on the kind of person they are or the times they've helped you in the past, but that's just a feeling that they will help you. It's not the same as the feeling of trust that comes from having faith in your friend. There isn't as much of a devotion to your friendship, only a belief that something will happen.
Like faith, belief is often used in religious contexts. People can say that they believe in God and say that they have faith in God. In this context, a belief in God is mostly acknowledging His existence. Meanwhile, faith is more of a devotion to God, and that placing trust in Him and His will is the right thing to do. It may be similar to stating that you believe in God, but it is much deeper and more profound.