I feel bad for the OP, that sounds like something kids would do to trick the teacher. But not knowing who's flirting with you that is just asking for something to happen. Playing those pranks are not cool and even the nicest person is going to get sick of it eventually. OP if she hasn't got out of her system by now, wait till you get married.

you cant tell personalities apart?

dude by now you should recognize at least a mole or freckle or something on her face or something. seriously

While she's sleeping put a mark on her somewhere to tell them apart lol. Idk so glad not in your shoes lmao

There should be a ring on one of them:p

Just make sure she signs the marriage licence first. If she signs the sister's name, then refuse to sign. If she signs the right name and you later find out it was the wrong sister, then it's fraud and the marriage is invalid. Note: this is assuming the laws are the same/similar as they are in USA.

Just get hot and heavy with which ever one is in front of you the twin will soon stop trying to trick you

No woman in her right mind would give up that special moment to trick her soon to be husband. Don't worry and congratulations. :)

I'd just refuse to marry anyone until they agreed to knock it off. Traditionally, it's their family that's going to waste thousands of dollars if the wedding doesn't happen.

Find subtle differences in their teeth, or a freckle, or their eyebrows, etc.