The awnser is be semi true means that some of it is true. The statement might be partly true. And semi means half.
I found more information on this word.
- "The statement might be partly true, the statement may be totally true but only part of the whole truth, or it may use some deceptive element, such as improper punctuation, or double meaning, especially if the intent is to deceive, evade, blame or misrepresent the truth."
- "Semi- is a numerical prefix meaning "half" The prefix alone is often used as an abbreviation when the rest of the word (the thing which half of is being described) is clear from context."