I have been asked several times whether it is okay to take blood oaths during courtship so as to secure the relationship and my answer is always non- affirmative: No! For one, I have had to have to pray with people and help dissolve blood oaths. Some of these people exchanged their blood by making cuts on their hands and then rub against each other while some licked their blood. Well, blood oath has spiritual significance and it is not what you dabble into as a result of momentary feelings that will soon fizzle away and you'll start regretting. What if we are so sure we will get married? Then you don't need the blood oath!
However among the Jews, taking an oath is more of a serious issue. I am not talking of ritualistic oaths, but just mentioning