delivered the opinion of the Court:

Appellant makes two contentions: First, that the affidavit of merit is defective in that it undertook to anticipate a defense by the defendant, and from this premise it is argued that the case should be treated as if there was no affidavit of merit. We must reject this, because if the affidavit contains all the allegations necessary to show a good cause of action, and it is not denied that it does, the circumstance that it states more than is required is immaterial. The excessive part may be disregarded as negligible. Of course, a plaintiff “cannot,” as this court said in Booth v. Arnold, 27 App. D. C. 287, 291, “convert his affidavit into a pleading, and, by anticipating a defense, require the defendant to negative or defend against such new matter of claim.” The truth of defendant’s affidavit cannot be questioned or traversed. For the purpose of securing to the defendant the right of trial the court must assume his affidavit to be true. Strauss v. Hensey, 7 App. D. C. 289, 294, 36 L.R.A. 92.

Second, proceeding, then, upon the assumption that the affidavit of the defendant is true, does it constitute a defense on the ground that Davis warranted that his health was good at the time he received the certificate, and that the warranty is false ? There is no statement therein that the defendant expects to prove either of those things. This is a fatal defect. In Hazen v. Van Senden, 43 App. D. C. 161, 164, Mr. Justice Van Orsdel, speaking for the court, said with respect to an affidavit of defense: “It will be observed that much of this amounts only to an averment of the belief of the affiant, without a tender of proof of the facts. In other words, proof of defendant’s belief would not bring him within the requirements of the rule. * * * ” To the same effect see Mearns v. Harris, 45 App. D. C. 536. It may be regarded, therefore, as settled in this jurisdiction that a mere allegation in the affidavit of defense that the defendant believes certain things to be true is not enough. He must go farther and assert that he expects *617to prove the particular thing upon which he relies as a defense. There is a distinction between saying that one believes a certain thing to be true and saying -he expects to prove it. Suppose in the case before us that the defendant had learned in some way from a physician who had examined Davis professionally that he was suffering from aortic regurgitation. It might say that it believed Davis was affected with heart disease, but in all probability it could not truthfully assert that it expected to prove the fact, because the physician would be incompetent to testify to it over the objection of the plaintiff. We hold, therefore, that the affidavit in question did not state a defense with respect to the alleged breach of warranty by Davis, and as this is the only defense attempted, the court was right in giving judgment for the plaintiff.

The judgment of the lower court is affirmed with costs.

Affirmed.