I'm making a cake similar to the one in the picture below and I am icing it in buttercream. I'm doing the accents in fondant and I am not really sure how to attach them securely. I thought about using royal icing to attach them but I figured the grease in the buttercream would break it down and it wouldnt dry. Any suggestions? Thanks in advance

Tiny bit of water would to the trick!

I use a little bit of buttercream.

I use a tiny bit of water also.. but if it is something a little heavier.. I would use some ri maybe or some gumglue

You could also brush a bit of piping gel on the back of your fondant... that is what I usually do.

I just use a little water brushed on with a small paint brush.

i use a little bit of water or buttercream which ever is available at the time.

i agree - either water (which is what i mostly use when going fondant to fondant) or a touch of buttercream, which might be better since you are going fondant to buttercream

Either will work but I use bc.