Don't share ( in) your love with one who doesn't understand / know about you.
= Don't share your love with a person not knowing about / understanding you.
Don't share your love on a man who doesn't understand you.
Don't share your love with a person who don't know you .
Someone who can not understand you does't have the right to share your love.
Stop wasting your time on someone who doesn't give a shit on you.