I have a specific point in a string I want a page break, I need some help with the regexp for it

the string where I want to insert a break is this

....ending of paragraph. Some Text: More text.....
What would be the proper regexp to put a break before Some Text?

From what I know of them I got [ ].+: which I know is wrong cause it takes out everything after the first word in the paragraph to the colon

and searching for Some Text isn't an option cause it is different on each entry, though im fairly sure there is 2 words in front of the colon in each