Nature is closely relates 2 Heart. it is just d possibility of what decision will u take on any particular condition.
i.e. if anybody says that he knows d nature of other person, it means that he knows in what condition other person will take what decision(or action).
D Nature is most imp factor in finding a true lover 4 anybody. 4 true love, it should be same or fulfilling each others needs... i.e. their likes & dislikes should be same n they should understand & support 4 each others problems.