Jim: Have you decided who you're going to vote for?
Chris: I still don't know. I'm kind of on the fence right now. Both candidates are qualified and seem great for the job.
Carol: Have you and your husband found a new apartment yet?
Shelly: Well, we're still on the fence about which city to live in. I want to live closer to the beach, but my husband wants to live closer to his work.
MEANING: to be on the fence means that you cannot make up your mind between two choices or alternatives. It means that you are having a hard time deciding on one thing over the other.