I have a little question, i asked myself
I have an instance a square.
And i have a second oject, this object create a line from his center to infinite.
There is a solution to know which side of my instance square is touched by the line (if the line touch the square)?

Presumably, you would use point_direction to get the angle and compare it to the angles of the corners of the square, if I understand the question correctly.

Once you know the point(s) of intersection, you can easily find out which side(s) are touched by the line, as its coordinates will partially match the coordinates of the rectangle.