Showing "this is secure" on credit card entry screen

Should I show some sort of "this site is secure" puffery (e.g. lock image, or some brief "this site is secure" boilerplate) on my credit card payment screen? If so, what should it look like? If not, why not?

I do want my customers to feel confident (as well as actually be safe) if they choose to enter their credit card details to pay my clients. I also want them to learn a healthy cynicism. Most of my customers are likely to have a very low level of technical knowledge about internet security and are usually either too trusting, and (in some cases) too suspicious of the wrong things.

I even had a customer call me up saying he wasn't sure if my payment page was secure because it didn't have any "padlock" image within the page. (yes, the page had a valid SSL certificate, the customer had the correct URL, and his version of Chrome was showing it with the green padlock with the "Secure" label at the time - after pointing this out he was happy to proceed).

I just feel it's a bit strange to splash a "this is secure" badge on a page because I know it means nothing, technically - because a phishing page would just as easily show the exact same badge.

Assumption: that my site is actually secure (let's just say I've tried my best and will continue to improve as much as possible).

For reference, here is the page as it currently stands:

Here's a mockup of what I mean:

UPDATE after some modifications: