There are things that are just hard to say, in person or in chat, (face to face even harder), yet, showing someone you got love toward them can be shown in alot of diferent ways,
depends on yourself , and your acts, itll help you get closer to them or further~
i dont actually know much about it in experience, though last time i had a crush in person, i kept it for myself and she never knew c:, but you should find a way, words or acts, in an intimy moment to show it i guess , you can take it easy and say things directly, or make it more poetic.
my advice? If you rlly want to tell her, et situation fluid, and when you have the chance, perfect moment, timing, intimy or anything, just tell it c:
Risk yourself! and good luck ^^