“Wisdom rests in the heart of the one who has understanding.” The woman, Wisdom, comes to rest, or is, in the heart of a person with understanding. The one with understanding will obtain wisdom.
“will she be made known among fools.” The question, “will she be made known among fools,” is a legitimate translation of the Hebrew text (cp. Word Biblical Commentary by Roland Murry, who also translates the Hebrew as a question). The answer to the question, coming from the rest of Proverbs, is that wisdom will not be known by fools, but there is a caveat: wisdom can be made known among fools.
Wisdom makes herself known even among fools although the fools themselves may never recognize her. Many wise people become wise by seeing the trouble and destruction that fools bring on themselves by their foolishness. In fact, some of the most profound lessons we learn in life come from seeing other people make mistakes rather than by making them ourselves.