How can I make my friend to love me back?

Hello doctor,

I had a best friend. She was childish in behavior but smart and independent. She loved me because of the attention and care I took for her (she used to miss her mother, who expired during her childhood). She loved me wholeheartedly, but I did not love her the way she did me. Time passed on. We loved each other for four to five months, then fights started. We argued a lot. I could not spend enough time with her, but she had made me her world. She had nothing else to do but talk to me and spend most of her time with me, which I could not give to her every time. She became upset whenever that happened, and one day, the relationship broke. We parted ways, and after two years, we started talking to each other. We became close, and this time around, I started liking her. I do not know if it is love, but I want her by my side. I get pissed off when she ignores me. I feel jealous when she get a crush feeling for someone. So I told her that I liked her. She said even if it was not serious, she was fine. But she would treat me as a friend. I want to step forward and ask her out, but I am scared that what if it fails again? What if she moved on completely and did not want me to love her? What if my feelings fade away? I do not want to let her go through the trauma again. I care a lot for her, and I want her happy. But I want her to love me as well. What do I do? How do I deal with this?

Kindly help.