Purchaser in good faith; doctrine of; duty of a prospective buyer. - Purchaser in good faith is defined as one who buys a property without notice that some other person has a right to, or interest in, the property and pays full and fair price at the time of purchase or before he has notice of the claim or interest of other persons in the property.When a prospective buyer is faced with facts and circumstances as to arouse his suspicion, he must take precautionary steps to qualify as a purchaser in good faith. In Spouses Mathay v. CA, we determined the duty of a prospective buyer: Although it is a recognized principle that a person dealing on a registered land need not go beyond its certificate of title, it is also a firmly settled rule that where there are circumstances which would put a party on guard and prompt him to investigate or inspect the property being sold to him, such as the presence of occupants/tenants thereon, it is of course, expected from the purchaser of a valued piece of land to inquire first into the status or nature of possession of the occupants, i.e., whether or not the occupants possess the land en concepto de dueño, in the concept of the owner. As is the common practice in the real estate industry, an ocular inspection of the premises involved is a safeguard a cautious a nd prudent purchaser usually takes. Should he find out that the land he intends to buy is occupied by anybody else other than the seller who, as in this case, is not in actual possession, it would then be incumbent upon the purchaser to verify the extent of the occupant’s possessory rights. The failure of a prospective buyer to take such precautionary steps would mean negligence on his part and would thereby preclude him from claiming or invoking the rights of a purchaser in good faith. Homeowners Savings and Loan Bank v. Asuncion P. Felonia and Lydia C. De Guzman, rep. by Maribel Frias, et al., G.R. No. 189477. February 26, 2014.