Suggestion [2]

"Let me join forces with you."

"No."

"Why?!"

"I think we have already gone through this many times," I said.

"Just let me join your team!" she said, urging the matter.

"I don't HAVE a team. I work alone. How many times do I need to tell you that?"

"Then get a team. Sooner or later you will wear yourself out and won't be able to work alone any longer. That's where a team comes in, and I'm the best person to be the first member," she said with confidence. 

There was a point in what she was saying, I was beginning to see it now. However, working with a team was simply not my cup of coffee. I preferred to work alone, that's how it has always been. 

If I work alone there is no one I have to doubt and the only person I need to trust is myself which makes things a lot easier. 

"I've already told you many times and I'll say it again. I don't want to work with you, and that is not going to change," I stated.