Black magic refers broadly to magic used to harm, and white used to help. This doesn't mean black magic is evil. To grow a garden, you need to protect it from weeds and inscects that would destroy it: as well as watering and nurturing it. Black can be necessary to protect yourself.
Pagan is a very loose term. It generally means someone who has religious beliefs outside of Abrahamic faiths (Christianity, Judaism, and Islam) but Buddhists, Taoists, Hindus and people of similar faiths don't always identify as pagan. It's a broad, vague term. It often refers to the worship of pre-christian forces.
Wicca is a religion. Not all Pagans are Wiccans, and Wiccans may identify as Pagan.
Occultic arts are a practice. People of any faith, or none at all, can practice them. Witchcraft is not tied to any specific belief system.
Practicing magic is not a betrayal of Christianity intrinsically. Plenty of people think verses like "Thou shalt not suffer a witch to live" actually mean something else. There is a lot of Christian themed magic, and even if you use a non Christian method it's not betrayal if you feel it's not often. Make your own path and your own way.
Love spells can backfire, but if it makes someone go psycho they had underlining problems already.
Financial spells can be odd things. If you only wish for enough to get by rather than wealth that should help you keep grounded. Remember, spells like that don't always work, and when they do, it can be at a time you didn't expect or a way you didn't suspect. They also are for help, they won't just make money appear a!lthe time and solve people's problems. Otherwise everyone here would be rich lol.
I hope this helps you, and I wish you well on your journey to understand magic.