Mileage Run Discussion - MR guarantee to earn elite miles?

Good day!
Singapore Airlines offer JFK to SIN (or any in Asia)

found this on ITA software by google

JFK-SIN/Asia $1480+ RT with fare code QLJFK going to SIN (not earning miles) while the Return fare basis code is HLJFK (will earn miles with United Miles through Star Alliance)

I asked a travel agent, he said he can book the ticket at $1700+ RT both of which is HLJFK (H class) meaning both ways to earn miles, total 22,000 close to Silver elite requirement

How can I guarantee to earn roundtrip miles?

Book the expensive ticket recommended by TA.

are you looking for travel insurance that will guarantee the mi?

if you are worried that irrops might cause you to be put on a non alliance carrier, you can ask for orc for the booked flights...