What do I do when a girl rejects a kiss?
Respect the decision
Respect her decision but don’t take it personally. She may just happen to be in love with someone else or you may not be her type. Don’t be upset about it, however don’t be suddenly very different with her than you were before.
I am not in favour of asking, you have to be able to gauge it with eye contact, smiles and then do the lean-in. You cannot really kiss someone by stealth, or even if you can, you shouldn’t.
Something to exclude first
Always worth as well checking you don’t have a breath issue. Just to exclude that as a reason why, in the absence of any more obvious reason.
Kissing onus
The onus is on the girl to help you to create a situation where you can repeat it if she actually would like to be kissed and was simply taken by surprise.
No biggy, you’ll see
But the main thing is, don’t treat it as anything major. It is a minor thing, really minor, as you will know for sure in due course even if your cheeks are burning today. No biggy; it is a smally of the smallies. You may feel that you have lost face, however, unless the person concerned was glanding some powerful acid that she herself was immune to, that is not likely to be the case in actual fact.