Ex Birthday

Today is my former crush's birthday, and I want to wish her a happy birthday, but I don't know how. At first, I only approached her because of a bet with my friend. I said that if I could make her like me, I would get some money. But somewhere along the way, my feelings became real, and I genuinely started liking her. The problem is that she already knows about the bet. She knows that I first got close to her because of it, and now I don't know what I should do?