The standard trust questions will also work. For example: If you left for a week to go to a conference, would you trust your partner not to cheat on you? If you confessed your darkest secret, would you trust your partner to understand and keep that information private? But, unlike these situations, needing long-term care is when you're most vulnerable, physically and emotionally. If you have the slightest inkling that the person you're spending your life with might—ever, for any reason—stick you in a dark corner with a TV, it's time to reevaluate.