"She wants to go to the zoo." Is stating a simple fact about something she wants to do right now. 她（想/要）去动物园 "She would like to go to the zoo." Is making a statement about how she WOULD feel IN THE (hypothetical) EVENT that the condition is fulfilled. 如果去动物园，她会很（高兴/喜欢） So, using "want" is more bluntly stating a fact. Both are used to suggest through implication a course of action to the listener (going to the zoo) but one is equivalent to saying "You should go to the zoo because she wants to!!" while the other is more polite: "If you were to go to the zoo, she would like it" or "You might want to go to the zoo, she would like that." Let's look at another example: A:"Want to come to the party?" B:"I would love to." here, "B" being more flexible and polite by keeping his answer hypothetical. What conditions could he be allowing for by using "would"? "B" is effectively saying: B:"I would really enjoy the party in the event that I am able to go, you permit me to go, and that nothing goes wrong and I actually manage to get there." It's safer to keep your answers hypothetical in the event that something like this happens: A: "About the party, it looks like someone invited too many people..." B: "Oh that's fine, I have plenty of things to do that day anyway." Now let's see what happens if you just use "want": A:"Want to come to the party?" B:"YES." A:"About the party, it looks like someone invited too many people..." B:"OH. I GUESS I CAN'T GO THEN. I'LL JUST FIND SOMETHING ELSE TO DO." A: (This is so awkward, I feel so bad because I know he wanted to go.) When declare to someone that you "WANT" to do something, the other person can't 退步 or have any flexibility, and you are forcing him to deal with the knowledge of what you want to do. By using "would", you are effectively saying "I would if that is possible, but you don't have to." 假如 X, 我会 Y. 但是不一定要 X. 这样留给对方一种“退路”比较礼貌