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.

My friend proposed me, how I can know whether he/she is in love or not?

Its quite simple to detect whether he loves you or not. Love can be easily tested when you are in trouble and someone have to do some sacrifice to get you. But it is really difficult to tale whether its love or infatuation at first sight. Generally, you can cross check with the behavior, its not easy to propose someone when you are in love. Sometimes person's emotional binding and self respect can cause problem in proper identification. Love/Infatuation also include madness , if your love is having good understanding and quite capable then he/she will take decision in favor of your which seems to be quite "self-less". Its better to ignore at first and give time and try your best to understand whether that person is in love or not.

Remember, one sided love can be quite dangerous, if someone truly loves you than make them understand then we can't proceed in this situations and leave gradually, but end up as friendship.

Its really easy to discover whether their is love or not. We already know what is love. So if we see symptoms of love then we directly say "They are in love" or in our dreams we imagine true love as mixed blessing of caring,understanding, respect,emotions,importance.