so you need to ask him straight to his face in a loving way if what he said in the past was what he meant or not. Ask him why he is dragging his feet now.

Perhaps a less confronting approach. Don't address his past behavior at all, the initial key is to ensure he feels safe with talking about his fears and concerns. He knows what he is doing and doing it on purpose, whether he is conscious of the decision or not. So, here's my approach.

Remove some of the pressure by telling him you realize the two of you may not be ready to buy rentals at this time and the two of you may never buy rentals. At the same time as equals in your marriage you require a quality conversation. You are asking him to show you the respect you deserve. That is of having an open and honest conversation.

Keep the conversation focus on the property and his opinion nothing else, not your feelings, not his, right now you're making it safe for him to talk. If he gives vague generalities, "I don't like the property" ask for specifics. Recognize you may not be able to help him become comfortable buying rentals, even then the two of you jointly have to decide what to do. (Is there any chance you've been pushing rentals down his throat?)

Mutually schedule meetings with him. If he doesn't show ask why he countered scheduled something, ask if you can rely upon him, ask if you can count on his being honest with you.

Just as he needs to show you respect, you need to show him respect. That respect isn't by one party or the other having arbitrary veto power, but by open and straightforward discussion. Where the outcome is respected by both parties and the pressure to change is dropped.