Ever make a promise? Or say, I swear to God! Making a promise, or swearing puts the promisor in restraints; it holds him prisoner to it. A promise made speedily, without fully considering it, often times are not kept. Sure, I can do it. Yes! I'll be there. I promise! The recipient of those vows, or promises, are expecting that they be kept. And when the promise to do or be is not honored, or rather when the vow is broken, relationships, whatever the kind, become fractured. There's no more trust.
How to respond in accordance with the scriptures
The Word of God says, 'Swear not at all; neither by Heaven; for it is God's Throne. Nor by the earth; for it is His footstool: neither by Jerusalem; for it is the city of the great King. Neither shall you swear by your head, because you cannot make one hair white or black. But let your answer be yes or no: anything more than that comes from the evil one (Mathew 5:34-37)