The phrase "I believe" expresses a person's personal conviction or acceptance that something is true or exists, often without requiring definitive proof. It indicates a subjective opinion or faith regarding a concept, idea, or situation.
The phrase "I believe" comes from the Old English word "belyfan," which means "to hold dear, to love, to trust." The root can be traced back to Proto-Germanic and Proto-Indo-European origins related to concepts of love and trust.