Dreams are complicated. They are a bridge from the subconscious to the conscious, and they can help us understand our true selves. Therefore, dreams usually don't tell us the answer naked, and we need to diagnose the truth hidden in abstruse places.
Dreaming that the girl I like will leave me forever: this is a dream caused by anxiety, because this dream probably represents the dreamer's fear of losing each other.
I dreamed that the girl accepted me: it was probably an expression of repressed desire to be closer to each other.
People who care more are more likely to appear in dreams. The relationship between you and her, background is the key to dream interpretation. Good luck!