Orientate orthogonal to point [closed]

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I have tried the following but I'm not getting any correct results so far:

tf::Vector3 fwd{1.0, 0.0, 0.0};
tf::Vector3 newFwd{(pointToHere - pointFromHere).normalized()};
tf::Vector3 ax{fwd.cross(newFwd)};
double alpha = acos(fwd.dot(newFwd));
tf::Quaternion newOrientation{ax.normalized(), alpha};

My idea is to construct the orientation with respect to my world frame, so all vectors I am using here have been appropriately transformed into my world coordinate system. My steps (as detailed in the code above) are as follows:

1. Get the new pointing direction via pointToHere-pointFromHere
2. Calculate the axis of rotation using the cross product of what I consider my old and new forward vector (which is the x-axis of my manipulator)
3. Get the corresponding angle using the dot product
4. Build the quaternion

In most cases where I get a valid pose, the direction of my forward axis is actually completely wrong. It should be pointing the other way...

Any ideas on what I may be missing here? The only thing I can think of right now is that the rotation axis may end up being incorrect..