Tell her or waiting......

should i wait her or tell her wat i feel rite now??? every time i with her always hear tat she dun wan get into relationship 1st... I so worry tat another guy chase her again. Before tat I hear tat she got feel with another guy, my heart almost broke liao tat time... i wan 2 tell her but i dunno how 2 tell her. ahhh.... pls teach me wat I suppose 2 do...???