Replace old text for PartialView - View only when the word appears.

It is so that if I write something specific in my text on the page then I should have shown a form on the page when writing the simple word that I want it to be overwritten with.

The problem is right now that I can in no way make my PartialView appear.

I've looked at these here:
https://stackoverflow.com/a/19208941

It causes problems when trying to just "run" as it is now and I get this error.

Microsoft.AspNetCore.Mvc.PartialViewResult

Code her:

return text.Replace("{{text}}", PartialView("ViewHelper/Email/EmailView").ToString());

i have C# 7.3 and .net core 2.1

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