I agree with Sam1148 - I pinch of baking soda will do it. You may mix them with escarole which is rather sweet tasking.
http://casa-giardino.blogspot.com/2010/10/escarole-and-beans-kick-it-up-notch.html

I can't speak for cannelini beans. But first, are these dried beans? If so, even vac-packed they might be old, and difficult to cook.

One trick for softening dried beans, bitter beans, that are old is to add a pinch.
Just a pinch of baking soda to the water at the end of the cooking time.
It will bring down the acid and allow the beans to soften and remove bitterness.

That trick is rather 'last moment' tho...and start with just a pinch, as the baking soda can quickly not only remove the bitterness, but any flavor in the beans.

I can't figure out why they are bitter, though I wonder if it's related to the saponin content. If they are horribly bitter you are probably out of luck. If they are only mildly bitter add fat, salt, +/- sugar as they can all temper the bitterness.

you dont really need to soak cannelini beans, they cook quickly enough without it

thank you, mrslarkin

I don't think I've ever run into that. I usually put some aromatics in with my beans, like carrot, celery, onion, bay leaf.

Not sure what you intend on using them in, but I'd season them well now with s+p, olive oil, garlic.