My thoughts:

Love means to love without an answer.

In my opinion this would be better as:

Love means to love without (needing) a response. 

Love means to love even when it is unrequited. Sounds fine to me.

Love means to love even when the affection is unrequited.

In my opinion it is better to say it rather than change love to feeling (or affection) as it keeps the original meaning

Unrequited means not reciprocated or not returned.

This was written in Turkish to begin with and It seems very pretty and english translation.

Thank you Henry for your comments, much appreciated!