Meh, you do not casts spells to do whatever you want for yourself. If you want something, you do not cast a spell and get it as it did everything for you, such as things that you should do by yourself.
It sounds like folks wish to cast spells for everything and anything.
A belief is basically distinct from judgment, which is a conscious mental act that involves arriving at a conclusion about a proposition (and thus usually creating a belief). Whereas belief is the mental attitude that some proposition is true rather than false, judgement is the evaluation of a proposition as reasonable, fair, misleading, etc.
Your beliefs are entirely up to you, your own thoughts and your own judgement. Your beliefs system isn't up to a spell, which won't replace your personal statement.
Ask yourself what you want to believe in. If you doubt it, perhaps it's not the best time to think about it. A spell isn't something to increase something which is entirely up to you and what you think (believe in).
Question yourself. Believe in what you want. Your belief system will get stronger and stronger through time ; no need to cast any spell to increase it.