The template
Subject: Re: {original subject}
Hi {first name},
Thanks for getting back to me. We don't do reciprocal links, since Google treats link swaps as a link scheme and it could hurt both sites.
That said, I'd still love for {product} to be considered for {article title} on its merits. If it's not a fit without an exchange, I completely understand.
If your readers would find {a genuinely relevant page of ours} useful, I'm happy to share {their post} with our {newsletter / audience} either way, no strings attached.
Thanks,
{your first name}