Some people claim that, in this "politically correct" climate, it feels impossible to ask someone you are physically attracted to have sex without coming across as a weirdo -- but these people fail to understand a simple concept:
Consent isn't creepy
You should ask someone if they would like to become more intimate, especially once you've established that you are attracted to each other. There are any number of ways to pose the question, and no need for a "sophisticated" line:
Hey, I really like you. I'm staying at a hotel nearby, do you want to come and spend the night with me?
Now, of course, you might feel nervous asking this of someone, but that's OK. It's perfectly normal to feel some anxiety in this situation, because it's something you want (probably a lot) and you risk rejection by putting it out there. Sometimes you just gotta go for it, though. The risk is worth the reward.
Side note: If she does say yes, then I recommend buying some condoms so you're prepared, but don't assume her consent to come back to your hotel means she wants to have sex. If she is at your hotel room, and things start heading in that direction, then it's definitely OK to get her clear consent that sex is what she wants.
Again, some people think all this talking and asking gets in the way, but I think you want your sexual partner to be fully engaged and enthusiastic. It makes things much more comfortable, playful, and ultimately enjoyable.
(Edit) To be clear: This is all about consent. Consent means that sometimes the person you ask might say "no", and, regardless of your personal feelings, you should accept their decision with good grace.