frequency function to FIR by frequency sampling method

i have function with respect to frequency. and i want to the function to FIR filter by using frequency sampling method
i make symetric value using that function.
the function is not linear phase. So when i do ifft, i coefficient is not real but complex coefficient
when i use coefficient = real(ifft(function)), the output is somewhat similar
is that right to use real value of complex coefficient???