If someone asks you out, you can to consider two things. One: whether or not you like them enough to date them. And Two: if you actually see yourself with this person.
Afterwards, when you have considered these two things, just either say: "Let me get back to you", or "Yes", or "Maybe". If you have to say "No", then do so with grace and niceness, because no one likes being rejected.
One thing, definitely NOT to do is shame them out! Especially if they are a nice person.
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