A young engaged man and his fiancée naturally have very strong feelings for each other. It goes without saying that these will be expressed after the wedding, but what expression, if any, is permitted in the meantime? And while we're on the subject, is the attraction of men and women to each other really a good thing to begin with?
"The day of rainfall is as great as the day on which heaven and earth were created." The sages liken rain to the creation of the world: Just as the expression "gevura," might, is used in relation to Creation, so is it used in relation to rainfall.
Jewish faith does not need rational proofs. It is above this. Because we witnessed with our own eyes God's Divine intervention in taking us out of Egypt, splitting the Red Sea, and giving us the Torah on Mount Sinai, we need no additional proof.