If you don't get a particular job, do you say you have "failed"? I would tend to say that I didn't get that particular job. I also tend to say, about relationships, that they "didn't work out". I don't use the word "fail" in relation to my own life too much, precisely because I expect that I will not give up. So in my own life, I consider that I simply have not succeeded yet. I don't see any reason why it should be different for children.

There were quite a few times while my son was growing up, when he felt like giving up because he wasn't experiencing success as quickly as he wanted to. I used to tell him, "just because you haven't succeeded yet, doesn't mean you have failed... it just means that you haven't succeeded yet." That helped him a lot, because he needed to see it from that angle.