Lies. About 7-8 years ago I did just this. She rejected me, I was kinda depressed for a month, but I cut all contact and started dating another girl. This was before I knew anything about game. We ran into each other at a party a few months later (I was still dating girl 2 but not BF/GF) and we ended up hooking up a few days later - and then dating for a year.
A few months into our relationship she said "I was thinking about you all the time when I didn't see you around" and "When you got a new girlfriend I was thinking 'uh oh new girl is taking my guy'".
Key is to just not care anymore about getting with her - keep busy and get with other girls. If you end up hooking up in the future, that's great. If not, oh well.