Listen to these sentences at the Talking People Podcast: Useful Language. Communicative Strategies 2
Sitting on the Fence (Being Undecided or Not Wanting to State Position)
Check out Hedging, too
I haven't a clue.
I'm not sure. (Meaning also: I don't quite see your point)
To be honest, I don't really know.
It's a difficult issue
It's a difficult question
It's a difficult topic
That issue is very sensitive
That's a sensitive issue
Well, it depends, doesn't it? (On the one hand, … On the other…)
It's hard to say
I've got mixed feelings about that. (I can see both sides of the argument)
Well, on the one hand... On the other...
We could even resort to:
I'm afraid I need to go now
I've got a phone call, sorry!
Sitting on the fence (read from Natural English)