Be On The Fence

Context #1

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.

Context #2

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.