Most people have a saying that "if it is there it would have happened already," or "when a guy likes you, he asks you out right away." They have time limits and if after a certain time the one you are eyeing on does not ask you out then give up. That isn't always the best advice or even the case.
Love has a lot to do with Fate and Timing. Sometimes it is all about timing. Being at the right time and the right place. There are times when a relationship did not work out in the past but it did years later. You could even have a friend for years, you never gave him a second look when all of a sudden feelings start to develop. It is about the timing. When it is supposed to happen it will happen.
Fate is when what is meant to happen will happen. You could look at the situation and say "never." That person you are saying never to may just end up being your future husband.
If you meet someone and there is flirting going back and fourth don't rush into it. If there is an attraction but either one of you is unavailable don't give up. You can't force feelings to go away. Be friends and see what happens. If it is meant to happen it will happen. It may not be when you want it to happen but it will happen. If you too are just friends than at least you have a friend. Sometimes someone is better a friend than they are in a relationship. So enjoy the moment, know that love is out there for you and let the universe and everything else in love unfold as it should.