My big dog (pictured) is a lummox. BUT every litter of kittens we've fostered? Uncle Casper has come into the bedroom, looked over the kittens and when they got out, gently placed them in his mouth and carried them back to the basket. One of those if I hadn't seen it with my own eyes moments. And he was tolerant of the kitten that has stayed - our Torbie. She was a dumpster find. She actually was submissive to the oldest pit bull - and that we think was a ploy on her part. Food is a huge motivator - or lack of it. She wasn't going to go any longer without a meal so she did what it took to stay in the home.
Then there was Woody. My dream cat. Followed me home out of the WOods, grey & white with a pink nose. OH a cuddler. I loved him. But he took a hiss and spit/spat, then swiped for NO apparent reason at Casper and then it was ON. Casper wasn't letting it go and would have killed him eventually. WE tried everything for over two months and finally gave up and rehomed Woody. It broke my heart.
I think within a month you will know if there is no way this will ever work out. Cats also take a LOT longer to warm up to new surroundings as a rule. But they are clever - she'll figure it out. But I like GCV moms suggestion and have used that before. We just sternly say BE NICE and mean what we say.
THe pit and the cat actually have been seen playing outside - but I swear the minute they think they're being watched? It's like EWWWWWW a dog/cat. lol
Good luck