今夜は帰りたくないって英語でなんて言うの？

Explainaing that you do not need to be home or you do not want to go home will give the indication that you would like to stay with the man you have a crush on for a longer period of time, possibly over night. By dropping a hint or telling them you would like to go to their house shows that you dont want to be alone tonight.

All these are indirect ways to explain that you are not interested in ending the night and you want to stay out with your date. They're suggestive without being too forward. If you want to be more direct you could ask him if he wants to "spend the night together". That is very direct and clear, but perhaps a bit strong, depending on how you say it.

Well, anything you say that means you would prefer to stay in this man's home than go home, would be taken as a romantic gesture on your part, so it almost doesn't really matter what you say! "I'm too tired to go home." "That's OK, you can sleep here." Or, "Who said I have to go home!" "Not me. You're welcome to stay!" Or, "Would you think badly of me if I stayed the night?" "No, of course not. I'd like you to stay!"

example "I would like to stay all night" or "I would like to stay the night" or "I don't want the night to end"

In the first sentence, you have been very frank about the reason why you don't want to go home and that is because you are enjoying his company. This can be very flattering to the man and he will definitely oblige. In the second sentence, you have not given the reason why you don't feel like going home, but it is obvious that it is because you are enjoying his company. In the third sentence, you are again being very frank and saying that you just would like to be here with him tonight although you don't mention your home. So, you may say: I am enjoying your company tonight and I don't want to go home. or I don't feel like going home tonight. or I just would like to be here with you tonight.