Have done 4 step but the last step still fail.

The girl keep teasing me to treat her to dinner but when i ask her out she said need to bring friend along which i disagree. This should obviously shown that i targeting her. The next day she again saying that if i willing to treat her she will gladly accept my offer. The day after again i ask her on dinner she again not willing to go alone with me but the way she reject me just make me scratch my head. She reject with very soft and sweet tone that i never heard off (kinda nice to hear) claiming currently she busy with work maybe after finish the report first.

I known her for 3 years and only recently try to approach her. Is she fooling with me or just shy. Or maybe she try to reject me without hurting my feeling.

Anybody wanna help me with the problem. Is there anybody facing such situation b4.