How do I not screw this up (date wise)?

So I got a fancy hotel for the next two weeks with my job and a female friend of mine is coming over for the night to check it out. I really like this girl and would love to well yeah and we so far have had nothing more than a platonic relationship since she is always hanging out with me and offered to come to the hotel with me alone I ume she is DTF but I have been wrong in this department before. I really want to tell her my feelings regarding this but I want to tread carefully because I don't want to damage what we already have friendship wise. if my main goal is to just have a more intimate friend and not a girlfriend. then how should I go about this. esp if shes seems to like some other guy who's not into her. Opinions and ideas welcome from girls and guys.