While still in disguise as the gypsy, Rochester speaks to Jane about Blanche. He reveals:
I know she considers the Rochester estate eligible to the last degree; though (God pardon me!) I told her something on that point about an hour ago which made her look wondrous grave: the corners of her mouth fell half an inch. I would advise her blackaviced suitor to look out: if another comes, with a longer or clearer rent-roll, he's dished.
What is Rochester's PRIMARY motivation for sharing this information with both Blanche and Jane?