Learn Spanish (Latin America): Estoy muy enojado por la multa.

In this sentence, por shows the cause or reason for the anger. It translates to "because of." You use por to explain why you feel a certain way, while para is mostly used for goals, destinations, or deadlines.

Could I use porque instead of por to mean "because of"?

No, porque means "because" and must be followed by a phrase with a verb, like porque tengo una multa (because I have a fine). When you just want to say "because of" followed by a noun like la multa (the fine), you must use por.

Why is it estoy instead of soy?

We use estoy (from the verb estar) because being angry is a temporary mood or condition. You use estar for feelings and locations, while ser is for more permanent characteristics.

Would this sentence change if a female speaker said it?

Yes! Adjectives describing feelings must match the gender of the person. A female speaker would change the ending and say Estoy muy enojada por la multa.