A lot of questions are easy. This one is not one of them. This one as an answer that varies constantly, changes from person to person. You may be willing to give up anything for that special person, or you may not, It depends on how you are as a person. Most people will know when they are in love though, It is a very strong emotion, and most people can detect strong emotions and feelings such as the one "Love" is.
Love is tricky. You will never know for a solid fact. You can only guess and hope you're right. You want the absolute best for them, and would do absolutely anything to make sure they have the best. Make sure they're treated the best. You look at them and know for a fact that that's someone you never want to live a day without. And you're able to tell.... After looking at them for like three seconds... How they're feeling. Because you are so in sync with them. The above count for any kind of love. Family, romantic, friends, even pets. But, who knows what of this is actually true. These are words from someone who hasn't experienced most of life yet.
Being in love is a feeling that is indescribable. You will not know when will it come, but you can recognize it when you are in love. If you cannot find a reason why you want to be with him/her, why you cannot live your life without him/her, then definitely you are in love. Another thing, if people of the world hates or doesn't like him/her and you are the only person who's standing next to him/her without knowing the reason why, then you are in love. you are truly in love when he/she commits sin unto you but then you did not understand yourself why you keep on forgiving him/her, when he/she keeps on hurting you but then you still wants to be with him/her then you are truly in love. Being truly in love involves sacrifices and understandings.
Because you feel it deeply inside ! When you want to be around that person all the time , and want to do things with just them . When you truly enjoy each others company . You know inside that this one is for you ! After almost 35 years of being married to the same great woman , not a day goes by that we don't hug , kiss , and say we love each other ! Hard to really explain ,but it's a different , very deep feeling ! I've always been a loyal loving husband and would do anything for her ! You'll know when the time comes and after you've been with someone a while and you still feel that deep feeling and want to do nice things for them that you know they like !
Good Morning Phlo! Love is that warm and fuzzy feeling you get when you are around someone or are thinking about them, but it also when they tic you off so bad you wanna strangle them but you still forgive them and want to be around them............that doesnt mean they should sleep with both eyes closed though -_-
Science calls the emotion of love being limerence (I didn't spell that right, but spell check hates me right now). It is when you put the value of that person far above your own, and are willing to sacrifice much to be loved back. That is why love can be described as love for your parents, your children, and your significant other.
I think that you know you truely love some one when you can easily edit you love them ( if your one of those crazy people that claim there in love after one date that is likely not true). Love is a feeling you get for some one that is so powerful you would do anything for them(walk through fire). Untill you find that one special person you love you won't understand the true meanings and feelings of love. Hope that wasn't to preachy for you!