Trying to simplify complicated boolean expression
Applying the distributive rule is the correct approach.

(X + Y' + W'Z)(WY + Y + W'Z)

But First simplify WY + Y to just Y.
(X + Y' + W'Z)(Y + W'Z)

Now distribute...
Y(X + Y' + W'Z) + W'Z(X + Y' + W'Z)
YX + YY' + YW'Z + W'ZX + W'ZY' + W'ZW'Z

Note that the YY' term disappears.  W'ZW'Z becomes just W'Z.
YX + YW'Z + W'ZX + W'ZY' + W'Z

Next note that YW'Z + Y'W'Z simplifies to W'Z.
YX + W'Z + W'ZX + W'Z

Note that W'Z + W'ZX + W'Z is just W'Z.  So finally we have...
YX + W'Z