Here are some examples of how the phrase can be used:
* "I don't believe you!" "Well, take my word for it, I'm telling the truth."
* "Did you really see a UFO?" "Yes, I did. Take my word for it."
* "I hear the new restaurant is amazing. I'll take your word for it, I'll have to try it out."
Essentially, it's a way of saying "I trust you, and I'm willing to accept what you're saying without question."