contrary to what one might expect · actually · contrariwise · why don't you

I'd certainly like to go and watch the match; it's just that I'm not sure if I have time.

I’d certainly like to go and watch a film, but I’m not sure if I have time.

That’s actually the truth.

The style of this item of clothing is good; it's just a bit expensive.

Then explain to me why you have Rima's pictures on your phone.