If I am understanding you correctly, you want to use to combine your strings into a single string, but maintain the individual rows. I would suggest using join.
for i = 1:length(trob)
trob(i) = join(trob(i),'\n')
end
The results of this is two cell arrays with all sentances strung together with \n delimiters. It is not pretty to look at in the workspace, but if you print it with fprintf you receive the format you're looking for.
>> fprintf(trob{1})
1.Check number
2.Should the issue be consistent
3.Understand the issue
4.Check compatibility >> % The next line starts here because we haven't put a \n on the end of the last line