Swear to Definition 1 of 3Pro Tip 1/3Sincere Assurance Used when you want to convince someone that what you're saying is completely true. I swear to you, I haven't seen your wallet. Pro Tip 2/3Emotional Weight Adds emotional intensity to your statement, showing you're serious. I swear to do everything possible to help you. Pro Tip 3/3Trust Building Used to build or reinforce trust when your honesty is in doubt. I swear to you, I was at home last night.