She can apply for a marriage settlement (fiancee) visa, to marry you in the UK. After marriage she can apply, in the UK, for Further Leave to Remain as a spouse.
Without knowing what kind of stock portfolio you have, it's not possible to say whether it is acceptable to meet the financial requirement or not. If you have to sell the stock portfolio, in order to turn it into "cash savings", then subject to certain conditions it can be used as cash savings immediately.
If you have documents showing that you are divorced, then that should be okay, but it depends on how the "divorce" was carried out. A "divorce paper" may or may not be sufficient.
The amount of cash savings required is 88,500 GBP. You haven't said if you receive any pension(s) or "benefits" (due to health issues), but that could change the level of cash savings required.
With respect, your post is a bit too vague to give exact advice.