How can I blend this shape into bottom layer without the harsh line

[newbie user guy]

I am trying to blend the top of this image from a black and into a white, but that it fades in very naturally to the top of the lower layer without the harsh line, showing the bottom portion of the shape. How can I do that?




Edit: resolved by blending from black to a transparent color

[mccoytest]

Can we get the image. without your blend attempt?