How to optimise SEO for misspelled brand name

Hi, I created a site called CoreBootSale, and at the moment it ranks #1 and #2 on Google when “corebootsale” is searched. However, when “core boot sale” is searched my webpage is nowhere on the results. I was wondering how I would boost the SEO for “core boot sale” without explicitly writing “core boot sale” on the site.
I’m pretty new to SEO so I don’t know if this is a simple solution or not.