If you are having difficulty solving a math problem and I help you, you do not have to take my word that the solution is correct. You can verify it for yourself.
However, if someone tells you that they love you, there is no way to verify it. For example, it is possible for people to treat you in loving ways and not love you. At the same time, it is possible for people who do love you to mistreat you. In the final analysis, there is no way to verify love. We either believe in people's word that they love us or we do not.
Your Creator is saying to you today, "I love you unconditionally. I care about everything that happens to you. You are my son/daughter in whom I am well pleased."
You either have faith that this message is true or you don't. Verification is not possible. The moment you accept that the message is true and act on the basis of it, you become a believer.