I'm sure you have been wondering why I have not talked about compatibility, understanding, respect and so on, well, that's because the fact that you are already engaged and thinking of getting married means all that and more are already in place, right? I hope the answer is yes, if you had to think about it then maybe you are not quite ready. To have gotten to this point in your relationship means you are both very in love, you are compatible, have mutual respect for each other, have long term goals and plans together and are so committed you long to spend the rest of your lives together.
Don't get me wrong no one is perfect and you can never get everything you want in another human being but these are the foundation that everything else will be built on, these will help you accept the imperfections in him/her and help you forgive and keep loving.
Now that you have no doubts in your mind that this is the one, you can confidently take that vow and waltz into your happy marriage.
All the best!