Enter Line-Break [Alt + Enter] at specific location

I know Excel is not the best tool for formatting sentences, but is there a way to insert a Line-Break based on a condition? (Either using Formula or VBA).

The situation is:

• A fixed-width cell, is a concatenation of 5 strings. Each of these 5 strings is a small sentence of 3-6 words; individually much smaller than the cell-width.
• 2 of these 5 are fixed (one at start, one at the end). The other 3 are results of their respective "IF" formulas.
• Hence, the final sentence wraps over 2-3 lines.
• I need the 3rd & 5th sentence (the whole sentence, all 3-6 words of it) to start in a new line, only if they are going to be wrapped into two lines.
• Is this possible?

So If the wrapping results in:
String1 String2 Stri
ng3 String4 Stri
ng5

Then change it to:
String1 String2
String3 String4
String5

Thanks for your responses.

However, there are two issues here:
1. A line-break should be inserted only if the string would not have fit in one line.
2. Each string itself comprises of 3-6 words; and is the result of an "IF" formula - so the resulting strings lengths maybe different and number of spaces in each string may differ.

I think my previous example was inappropriate with regards to point 2. A String in my case can be "S tr ing" (3 words) or "S t r i n g" (6-words) or even 4 or 5 words; So the "Instance_Num" in the "Substitute" formula needs to be dynamic (or maybe I can prefix a special character to the start of each string, and then substitute that character instead of space).

But first - how do I check if a string is going to wrap itself over 2 lines or not? Any ideas.

Mate,
That was one brialliant idea - to check the "RowHeight" for a given column width.

Here's how I achieved the desired outcome:

• I prefixed a "#" at the start of all the multiple-word strings.
• Then I created an extra column (a Pseudo-Column of exact column width). I use this pseudo-column to check any change in row-height before and after a string is concatenated.
• So, if the row height increased, it meant that the last added string was wrapping over on two lines; and I then substituted the "#" with Char(10).
• If not, that meant the new string was not wrapping and then I simply substituted the "#" with a space "_".
• Finally, just delete the pseudo-column.

It is not the most elegant solution, but it works .
Thanks again!!