Promoting self without feeling conceited

I have just created my first video series for a new business I am starting (which was a huge step outside of my comfort zone) with my business partner. She is a LOT more experienced then me having created hundreds before. She wants me to take the lead with this project and has tasked me with creating a landing page and promotional sequence. I am really struggling with self confidence of how to promote the videos. As in writing the copy. I told her that I struggle with writing copy as I don’t feel comfortable talking myself up and it just feels ‘showy’ and ‘arrogant’ and she told me to ‘just get over it’ and now I feel hurt and confused and so my question is how do I best address this?

I put it into the model

C: write promotional copy
T: I don’t feel confident talking myself up
F: Arrogant / conceited
A: write some long worded drivel
R: no one watches the videos as they aren’t appealing

But not sure where to go from here, any advice would be wonderful!