For me it better to be honest for my self and other.

Don't play with they feeling,think that you can make him happy with accept his love but in fact you not love him. Just imagine you stand in their position when you really love someone and then you know that he/she not love you, he just pity with you. what do you feel inside? so hurt right.

Except you sure you can love him back, but still you must to be honest to say that you will try to learning to love him/her.. It's not automatic you need time to know him/her better until you have the same feelings but if that feeling not come yet better not to be force.

It is better be loved than to love someone but he doesnt even know or care about you. It is hurt too much. But if someone love you and you dont love him at all. It isnt good feeling also. I would prefer you love someone and someone love you also. It is the best one i think.

Both

As for me it is better to love because this feeling have to through everyone,despite the suffering.

That's really awful, when someone, who loves you and is waiting for mutual feelings from you, can't get one. Harder, when he asks you looking into your eyes: "please, tell me that you'll always be with me". What would you tell him? I think nothing. After some time you'll go off, if you have at least a small part of humanity.
In my opinion, I wouldn't allow myself to make that man unhappy. Let him be loved and happy next to another person.