Are there any practical ways of suggesting to a woman that I am completely disinterested in forming a relationship with her?

It's not the first one to make advances towards me. I have so far successfully ghosted 4 girls at my current school that have exposed visible interest in getting to know me. They seem to have given up.

However, this time my strategy of acting absolutely stupid and oblivious does not work well. Previously, this strategy worked out perfectly - all four of them stopped bothering me after 3-6 months, and, thanks to my skill of acting like the most oblivious son of a gun, they don't seem to be angry at me.

This one is far more determined and a bit obnoxious, luckily, she has no opportunity to talk to me after school.

She's also quite better at seducing than the previous ones, but I'm seriously indifferent and immune to that, so she has not caused the development of any romantic feelings for her in me.

I have not shown even in a slightest way that I am going my own way to anybody in real life.

She may not understand, how annoying the thought of 'giving up education, career and my later, great ambitions for a worthless, hazardous and temporary bond is.

So far I have been doing great and learning hard, but I need to get rid of her anyway.

I'm 19.

Amy tips? Any subs that could assist me? I want to do it softly, cleverly and gentlemanly.