As an experienced WordPress developer and Payment Gateway integration specialist, I should be your top choice for this project. Over the course of my 7+ years in the field, I've not only built a deep understanding of various payment methods but also have had extensive experience incorporating popular payment gateway services into websites - and this includes providing added security for online transactions.
Moreover, my proficiency in HTML, PHP, CSS, and other relevant skills will prove very useful in ensuring that the payment integration process is seamless and harmonious with your existing website structure. Additionally, I'm fluent in English and Spanish - guaranteeing hassle-free communication throughout the project.
To further convince you of my suitability for this task, I'd be more than happy to share examples of projects where I've completed related work to the client's utmost satisfaction. In these cases, the websites experienced improved speed (something relevant to your needs), better functionality, enhanced security, and, most importantly, facilitated smooth online transactions. So let's get started on enhancing your website together!