How can I get men to DATE me without having ?

I am a college educated 25y/o woman, single no kids. I have a full-time job and have been told that I am very attractive. I am a ual person and give off that energy (from what I've been told) but I am tired of one-night stands and flings. I meet men ALL the time. From all walks of life and it seems, that no matter how reserved I try to come off---they always are propositioning me for . I am trying to get a committment BEFORE . But how do I show interest or keep a guy around consistently without him thinking I'm being a tease? I have toned down how I dress and I even change topics if a guys starts to speak ually---but why aren't guys trying to get to know me and DATE me seriously, take me out---why do I have to play like a referee in not letting them get ? What am I doing wrong? Should I just start telling guys, no sex without a committment or should I just let things flow...