If you have to rely on a message board An answer to this question, then this is not a topic your speech should cover. Furthermore it is a toast, not a speech, which means it should be a brief statement to congratulate the couple and wish them well. Two minutes max. They do not need your input about what love is, And the guests do not want to hear it either.
Just say your name, Congratulate the couple, tell them they look nice, tell them that they’re nice people and good friends, and then ask the guests to raise their glasses and join you in a toast to their health and happiness. The end.