How to get a smooth Vector2D transition?

I’m trying to use the vector2D interp to move between two positions. The problem is, the shorter axis will complete its interp faster than the longer one, meaning the path isn’t a straight line.

Here’s what I mean; the one on the left is what it’s currently doing. The right is what I want. Any help appreciated!

Thanks you’re right, I realise what I was doing wrong. I changed it to interp X and Y individually and got muddled.

This produced a perfectly straight line: