Hi,

    The fact that she chose you to be her boyfriend  over the others should make you self-confident.  If you are doubtful, have a heart-to heart talk with her and ask her if she is sure about her love for you or if she is still thinking of exploring more possibilities.  It's better for the both of you to be honest with each other  now than to be married later just to find out that this is not what she really desires. 

     She must have seen better qualities in you for her to choose you.  Try to be more loving and caring to her.  If after your heart-to heart talk, she'll tell you that she still wants to date other men, then try to be understanding.  She has the right to find someone compatible with her and who she will be happy with.  It's just like shopping in the department store.  One usually wants to buy the best item so that it will last longer than to just go inside the store, just pick up the first thing that she wants to buy without checking out the other brands down the isle.  Haste makes waste.  So give her time to choose who she really thinks will be good for her.  If she decides it's you, then just be happy.  If you're not the one, then just accept it graciously.  There is one good woman for you out there, who will love you and  care for you for a long long time.  It's not easy to find the right person, but you just have to be patient.

Take care and good luck to you.