In the end, there is no formula and no rote substitute for intellectually honest Christians seeking to care well for one another and to faithfully apply Scripture to infinitely varied relational circumstances.
So with all that said, let's consider how the principle of caring for one another well in the early stages of a relationship might look.
Then — in addition to actually thinking and praying about it — ask one of your pastors or elders whether he knows him and what he thinks.
If the pastor or elder you ask doesn't know him well, he can guide you to a trustworthy source that knows him better.
If you don't have even information at that level, feel free to tell him that you want some time to think and pray about it (that is, if you're not sure at that point that you're not interested).
Let me say it again: We're trying to make intentions clear, here, not asking anyone to commit to go the distance with no information.
There are biblical and unbiblical reasons for a man to initiate with a woman, and there are biblical and unbiblical reasons for turning a man down.
That's where the following practical suggestions come in.
Note the phrase "practical suggestions." These are not sacrosanct biblical principles.