Shall I use "without doubt" or "without a doubt" to start my sentence in an essay?

Without a doubt is the more common/grammatically correct term

Both work, but the expression "without a doubt” is generally employed more frequently ...

Explanation:

Alternatively:

certainly, doubtless, assuredly, beyond (a) doubt, etc.

our founding fathers introduced the revolutionary idea that each person's desire to pursue their idea of happiness was not self-indulgence, but a necessary driver of a prosperous society. they created a government to defend that right for everyone.

the play romeo and juliet was one of the most famous love tragedies ever written. this love story unfortunately had a fatal ending. many people argue over why the lovers had died, was it over free will or fate?  

the death of romeo and juliet was partially because of free will. the fact that romeo and juliet got married knowing that there was a bitter feud between their families, the montague and capulet’s. this feud brought on many problems, such as the murder of tybalt by romeo. juliet knew that this might be a problem for her and romeo. juliet had said: “what’s in a name”? which explains her ill fate of being a capulet and romeo being a montague. when romeo tells his servant “ ay, mine own…show more content…

i believe they had died over the love they had for each other, strong enough that their lives could end so suddenly if something horrible had come between them, and that was exactly how it happened. this tragedy occurred within five days of the two meeting, they experienced love at first sight, got married and quickly were dead. free will became a part of this when juliet decided to take friar laurence’s advise in inhaling a potion that will make people assume she is died but will awake in 42 hours prier to when she took it. when romeo had heard the news that juliet was dead, he assumed it was true, and responded with the line; “well juliet, i will lay with thee tonight”. to me this line indicated how he feels for juliet by dying in her will. the fact that free will didn’t take control of the story; it left fate to be the murder of the lovers. fate first kicked in when their eyes met at the capulet party. when romeo and juliet spoke, their words had powerful contentment; they had such a strong feeling for one another that they could lay in each other’s arms forever. their happiness didn’t last long; there were many reasons for this, for example; the marriage lord capulet arranged between paris and juliet. i believe that the plot of the play thus far leads the audience to believe that the deaths were a result of fate. the last act will determine once and for all if it is fate or free will. romeo again challenges fate.

explanation: