1991 Buick Century Not ordinary starting problem

A couple of days ago, car started having some problems starting up, until one day I turned the car off for 3 minutes then tried starting back up, and the started sounding like it was getting juice but not enough, just to say turning a little bit. Tried boosting, but nothing.

Took off the starter, tested it - it was good.
Checked the continuity of the cables from the battery to the starter - they're good.
Got a load test done on the battery - it's good.

After I put everything back together, the car started with a boost, I let it run for around 10 minutes, then brought it to my driveway, shut it off and tried to turn it back on, but it did the same thing as before.

I have a bad water pump bearing, so tomorrow I think I will try starting the engine without any accessories to see if it's a seizure problem, but if it's not, what are other things I should look into?

It has the 3.3.