What are the arguments of Decius Brutus to induce Caesar to "come forth" in Julius Caesar?

Decius argues that Caesar will be considered cowardly and that the senate is planning to give him a crown.

Decius Brutus was a trusted lieutenant of Julius Caesar, so when the assassins needed someone to make sure that Caesar made it to the senate on the day they planned to kill him, he was the logical choice.  Decius was also very persuasive, and for this reason they were sure that no matter what, Decius could get Caesar to the capital.

When Cassius worries that Caesar may not come on the Ides of March, Decius Brutus explains that he can make Caesar come no matter what.

Never fear that: if he be so resolved,
I can o'ersway him; for he loves to hear
That unicorns may be betray'd with trees,
And bears with glasses, elephants with holes,
Lions with toils and men with flatterers … (Act 2, Scene 1)

Caesar trusts Decius Brutus.  He seems to value his advice.  Of course, there is no reason Caesar has not to trust him.  He has no idea what someone so close to him would turn against him.  So when Decius Brutus shows up, he is not the least bit suspicious of his motives.

Caesar tells Decius that he won’t go to the capital that day, and tells Decius to tell the other senators that he is sick.  Decius responds that they will laugh at him and want to know the cause.  Caesar responds that his will is the cause, and that is all they need.

Decius does not give up.  When Caesar tells him about Calpurnia’s prophetic dream, which she has interpreted as meaning that Caesar is in danger, Decius’s golden tongue finds a way to twist the dream into a positive.

This dream is all amiss interpreted;
It was a vision fair and fortunate:
Your statue spouting blood in many pipes,
In which so many smiling Romans bathed,
Signifies that from you great Rome shall suck
Reviving blood, and that great men shall press
For tinctures, stains, relics and cognizance.
This by Calpurnia's dream is signified. (Act 2, Scene 2)

Caesar falls for it.  He prefers Decius’s interpretation to Calpurnia’s.  He does not want to seem like a coward, or someone who can be persuaded by a woman.  When Decius tells him that the senate plans to give “a crown to mighty Caesar” that day, and they may change their minds if Caesar does not come, that seems to be the clincher.

Why would Caesar refuse a crown three times from Mark Antony, and then greedily agree to go to the senate when Decius Brutus tells him that he is being awarded a crown?  There could be several reasons.  One interpretation is that Caesar really did want to be king, and the crown on the Feast of Lupercal was just a way of testing public opinion.  Refusing it was a publicity stunt. 

Another interpretation is that Caesar did not want to appoint himself king, but would accept the senate doing it.  Of course, he might have also just wanted to go to stop them from crowning him king, since he vehemently argued that he did not want to be king. Whatever the reason, Caesar went to the capital.