Many of us when we encounter competition in dating we tend to want to deal with it through the power of the muscle. In most cases we become very violent and try take the law in our own hands. Their is no need for all these, you will only hand yourself in the wrong hands with the law enforcers. Take your time and relax, identify the problem and then from there get a regal means of sorting it out.
Don't even engage your competitors in the war of words just deal with your girl she is the source of the problem and she only can provide the solution.
Always let her know how badly she needs what your competition in dating is offering, never argue with her or try to prove to her how useless your competitors are. This will only help her move closer to them. Remember always to congratulate her for the good qualities and the wonderful things about her, don't forget to do this as often as possible. Let her feel special infront of you and you should plainly let her feel that the guy to win her will be the luckiest one on earth. Make her feel as if the other guy will be the most blessed man on earth to get her as his wife. This will work wonders towards you and note this kind of hype quit unlikely will also be coming from your competition in dating; she will no doubt stick with you, women are made of sweet words.
Befriend her friends also this will work very positively towards your relationship. You will learn from her friends what she likes and her preferences. Let it be known to them that you are interested in her. You will be able to learn from them what her expectation are or whether she has any feelings toward you. Her friends will also pass a word to her about you and she will realize that you value and care for her. This will bring her very close to you and you will have beaten competition in dating.