presentation – Creating a donate button but for a third party

I just created a free website that offers a fun service to anyone who wants to use it. One thing I would like to do is add a donation button, but donations are not for me. When the user clicks the button, he goes to the fundraising page of a third party website.

How can I clearly and unambiguously demonstrate that the Donate button is not used to donate to the website? I think people will be more likely to donate if the donation is for a good cause rather than directly on the website. Until now, I've tried a button with the text "Donate (for a good cause)". I've also thought about changing the text to "Donate to X Charity". However, if I use this method, users will wonder what charity X has to do with the website. In the end, I want to tell the user "if you like this site, consider donating to my favorite charity."

My website header with the Donate button:

Site header