Commitment. The state or quality of being dedicated to a cause, and/or activity. To me, it is something greater than a simple promise, because no matter the situation the commitment will be fulfilled. Love requires commitment to succeed, soon-to-be-parents make a commitment to a child when they conceive. Of course, similar to promises, commitments can be broken - marriages being the biggest example.
Marriage is the joining of two souls in ceremony, to not only bound them to one another in public, but to remain faithful, and to remain by one's side for eternity (or until death, but I find that I will remain with my fiance beyond death). Couples make this commitment together, and then after some times that commitment is broken. Either by adultery, theft, or by abuse - either way, marriages end in divorce because the couple responsible for their bond let it fall to pieces. Now I'm not saying that neither one tried, as there are plenty of people who try to fix their marriages, but I'm simply saying that it gets the point of no return for either side.
Of course, when one lets the relationship fall through the cracks, what does one do? Most try and catch the next big "fish" in the ocean, have one-night stands, or in some cases - some people try and get back with that person because they cannot find anyone else (of course, there are the legitimate ones who had a misunderstanding and are able to correct it, but more often than not they done goofed and they are not getting back with them). There are also those that we see in our everyday lives where they are "off and on" all the time, and those people we would probably like to smack some sense into.
Naturally, to form a commitment, one needs some simple ingredients (and no, we are not making "The Powerpuff Girls" honor, respect, dignity, some humor, a lot of wisdom, and an infinite source of love (yes, cheesy, spare me). You can only have so much of one quality before the potential person begins to see the flaws - and when they do, they are going to need more than one good quality to outweigh the bad, and it works in reverse too.
Overall, commitments are sacred to me (and hopefully to you as well) and should be held and seen through to the very end, as much like promises, they mean so much to the person who has you commit to them (or their cause). Otherwise, there could be consequences down the road, such as an angry mother and father-in-law chasing you with a loaded shotgun or karma biting your behind when you are trying to suceed in whatever it is you do.