1) read the number back and change a digit, if she doesn’t correct you it’s fake… Move on.
2) the only way to get good at talking to girls is to practice and get rejected as many times as possible. Rejection isn’t an insult, does she have a bf? Did she just break up? Does she have a family situation? Is she just doing her own thing? Guys assume they get rejected because they are not attractive. NOT TRUE. Even if a girl is physically unattracted to you, you can get but hurt or improve. Look as good as you can? Great. Your not getting rejected because you are not attractive enough. You’re getting rejected because she doesn’t feel comfortable (or for any reason mentioned above, which you have no way of knowing) and because you are not confident enough. People don’t remember how you look, they remember how you make them feel.
Be confident (do this through practice, get rejected as many times as possible), make her feel comfortable with your presence (practice practice practice). Learn how to talk to woman (practice)
Rejected? Rejoice. For that is how you learn and that is how you will find love.