What is the best way to make someone understand that you love him/her?

Its always better to do some field work before taking a step ahead. Try to be his/her friend first. Try to come close and understand your love. Workaround to find her liking, disliking, ideal character of his/her life then try to mold you into that shape. Generally its always better to work by giving little hints and the propose someone. If you are having any doubt, don't wait propose your love. Proposal is most important part. If you are thinking that you should not do it due to some specific reasons or lack of daring then change your thinking. Its extremely necessary to propose your love. If conditions are non resistible then change timing. Remember once you missed, you may not get second chance. Its also better if you are not having positive expectations from other end.

If your partner is quite intelligent and having very good understand then he/she may try to relate it with past occurrence to cross check.