Diana's assessment would likely be persistent.
Step-by-step explanation:
From the given excerpt, For the first time Diana started speed dating i.e she spends 5 minutes with every partner she meets. This means that she takes a continuous effort to meet and choose the right person.
In that process she likes to meet a man again. She is taking an accurate decision with the help of her own assessment.
From this it can be inferred that the assessment she made is very persistent. That is, she obstinately or firmly continued to meet the person that she would like.
So, it can be concluded that the assessment of Diana would likely be persistent.