Though I've worked for a sales organization for most of my career, I've never been a sales-person. I always thought I wouldn't be able to handle the rejection (sales people hear no a lot more than yes).
But the truth is - I can (and do) handle rejection quite often. I'm getting better at it, too.
It occurs to me that being rejected is a little like training for a race. The first time you run, you think you're going to die. This is it, this is the end. There's no way I'll survive.
But you don't die - so you try again. After a while, you start to realize that not only are you not dying - it's actually getting easier.
You're building up endurance - or in the case of rejection, a tolerance.
The problem with that tolerance is that sometimes, part of it comes from an increasing sense of apathy. In order to manage the rejection, your heart and mind have gotten together and shut down those parts that allow people to get close.
Which is great - rejection doesn't hurt anymore! But that's a double-edged sword - you're numb to the rejection so you can't be hurt, but in order to be numb, you can't find the relationship you want.
When you're training for a race, as things become easier, the right thing to do is push yourself a little harder. Increase your speed, or your distance, or make the course a little harder. Once you hit the level where you don't feel any pain, it's time for a new challenge.
That's the only way to get the desired result. If you're training for a marathon, you can't stop when a 5K is no longer challenging - you'll never run the 26.2.
I suppose the same is true in dating. Once you can handle certain scenarios, you have to open yourself up to something more. Push yourself a little more; find a new challenge. Prove to yourself that you can handle the ultimate rejection, so that your heart and mind are ready for the ultimate triumph.
Finding a relationship isn't a sprint, it's a marathon. You're either in it for the long haul - or you're not really in it at all.