Such vendor and vendee shall make and subscribe an affidavit in substance as follows: We severally swear that the foregoing memorandum is made for the purpose of witnessing the sale and the consideration therefor, and for no other purpose whatever; that the amount therein stated is the true consideration, and has been actually paid by the vendee to the vendor as specified in said memorandum; and that said sale was not made for the purpose of enabling the parties to execute said memorandum, but was an honest transaction entered into in good faith between said parties.