The girl you are going to marry is undergoing rejections as you are... and so did Christ.
This is something you probably know already: you will probably experience rejection (too) many times in your life. Do not take it personally. If you took the risk to prayerfully ask a girl out (read: Pray while you ask her out), you are an honest, respectable Christian and the outcome will not change that. Recall when you were applying to college or for a job, did you stop applying elsewhere because you get a rejection? No, on the contrary, the fact that you got rejected is reason to apply to others.
God may allow you to be rejected by the wrong girl so that you won't be rejected by the right one
It sounds cheesy but it’s true: rejection is one of life's many challenges that God allows to help us grow spiritual muscles. Challenges expose our limitations and drive us closer to God. Rejection from one girl may be an essential learning moment you need in order to become prepared for the girl God has prepared for you. There are steps you cannot skip. There are prices you need to pay in order to gain.
A rejection may well be a time to stop and reflect. If you keep getting rejection after rejection (say more than 5), something is wrong and you should find that out and change it. Maybe you need to work on yourself, or maybe you need to learn how to pick the right girls to ask (Read: The only thing you can do to boost your chance with a Christian girl should have been done before you met her). This is called growth. It is the necessary process of understanding yourself and what you want and aligning it with what you actually need. The pain you are feeling is growth pain allowed by God for your ultimate good.
She is undergoing rejections as you are... and so did Christ
Sounds tiresome? Sure it is. It is supposed to be. But know this: the girl you will eventually end up marrying is probably undergoing the counterpart of the same process now. This enables her to mature and prepares her for a good relationship with you when you two meet in the future.
Actually, the girl who rejected you today will likely also undergo the same thing. This is called life. Nobody is immune to rejection. However, God will never give us more rejection than we can handle. Because He understands rejection better than anyone does. Christ on the cross was rejected by everyone including His closest friends. He was even cut off by God Himself in order to bear all of our sins. But all this was temporary and served a purpose. He came out of it triumphant. God will never hand us rejections without a larger purpose. He never jests with our emotions for fun!
No girl owes you a date, just like you don’t owe any girl a date
There is something else you need to understand: no girl owes you a date. Just like you don't owe any girl a date. As Christians, we don't owe anyone but God. If a girl you do not find attractive likes you, you are not obliged to date her. Similarly, just because you daydreamed about a girl every 5 minutes, or poured her a drink at every party, or even changed every single bulb in her home, does not mean she owes you a relationship. Entitlement is against Christian faith. Indeed, if a guy believes he "deserves" a certain girl, he loves only himself and it is more likely that God will make her reject him to protect her from a selfish man who is immature in faith.
How about nuclear rejections?
Right, so nuclear rejection in the American Church is very real. To understand and avoid this danger, read: Why Christian girls tend to make nuclear rejections and how to avoid getting hit.