Thank you for your question.
Essentially, especially if we're going to be presenting our information to obtain to a judge or a justice, they have a guideline themselves. It is, in fact, subjective, but they were trained to properly assess whatever grounds are being put before them. They have their own tests, which will test whatever grounds are being put before them, and they will attribute the level of grounds which have been or have not been met.
We can present only what we learn, what we collect in terms of evidence. If it does not meet the grounds and the judge or the justice feels that it's either “to suspect” or “to believe”, then, quite simply, it's not signed and not attributed or active as a warrant.