is she really telling me the truth =(

So my best friend and i have known eachother for about 4 years and things between us have always been fin and dandy i nvr doubted her for a moment but recently i fell for one of our guy best friends and me and him where talking but it didnt go anywhere. later she told me that he was trying to date her and she told me that she would nvr date him and that she didnt see him like that and that she only saw him as her best friend. So i believed her and never doubted her not for a second. she kept telling me how he kept looking for her but she assured me that him and her would always remain friends and nothing more. one day she got stranded at an event and had to call him to pick her up. when he ggot there she had already had a few drinks. wat she told me wat supposedly happend she had said that he asked her to give him a chance but she told him no cuz she already had a bf.. yet when i looked through her phone specifically through messeges to him as i usually did.. there i read that she had told him him she would not date him because of me.. could it be that she may have feelings for him and is not telling me this? how should i approach her with this? do i even have a right to ask? i would hate to loose her over a boy but if she trully isnt being honest is it really worth it?