You may want to set up a pet gate or x-pen so they can sniff each other without engaging directly. This will allow them to introduce themselves. Avoid letting her into his room – this will make him more territorial if he thinks his environment is being threatened.

This is what I do with Theodore and Olive, the resident kitty. You will want to closely monitor their interactions, though. It may take a very long time for them to fully come around. After a few weeks of allowing them to sniff one another, you can start letting them have short (15 min) interactions in “neutral” territory – somewhere outside of his room. I recommend spraying kitty with a little water if she starts getting predatory. This will teach her not to exhibit that behavior around the bunny. Reward her with a treat or affection if she ignores him – this is the kind of thing you want her to do. If she starts getting really aggressive, then of course separate them immediately.

Like I said, the “bonding” process can take a very long time and may never quite catch on, in which case you’ll want to make sure they never get the chance to hurt one another.