Really don’t want to share a hotel room with a friend...

You need to stop dodging the question and tell her "no, you're not interested in sharing a room with anyone." I attended a family member's destination wedding alone last year and one of the MOB's single friends kept asking if I wanted to share a room.... Um, no. I got it, the rooms were really expensive, but I wasn't willing to share a room (and likely a King-sized bed...) with anyone, but especially not a long-time acquaintance. This issue here is that you need to be assertive and tell her no.

UGGH, just say no.. What if FH likes to walk around in underwear (or less!). She is nuts.

Of course she keeps asking you, because you seem to not be giving a clear answer.

I agree with Mim, don't EVER give excuses, people will try to "solve." Like let's get a suite and share that. Just say no, as quickly as possible

I've had 8 weddings this summer and we split hotels with other couples on 3 of them because it was cheaper to split a hotel suite then to get our own rooms. And with plane tickets and wedding gifts and the fact we are planning our own weddings, we appreciated saving the $500 over the three weddings. Your response of 'We aren't in college why would I want to do this?' is super condescending and frankly quite insulting to me. I'm in my 30s and FH his late 20s and us splitting hotels isn't us thinking we are still in college, but purely a money scenario. It isn't at all weird that your friend is asking and there is nothing wrong with wanting or not wanting to split the room. If you are being wishy-washy about it, I understand why your friend is still asking. If you don't want to do it - say no. If you haven't actually said 'no' then you can't be annoyed at another person for not understanding that your vague responses means no.