[smug]

on the other hand why should Lincoln had trusted the peaceful intentions of the confederates when every action they had made to date had been desinged to only escalate the tensions?

Perhaps as an effort to deescalate those tensions? And then maybe an open letter for all to read such as this.

To my dissatisfied fellow countrymen,
In an effort to keep our country from the brink of war. Although, like my predecessor, I do not believe there is a Constitutional right to secession, propose to meet with the commissioner that you have sent to Washington, and ask that if this be agreed that you in a humanitarian gesture supply the troops at Fort Sumter with rations. Arbitration is far better than war. let us both back away from this brinkmanship and see if our Mystic Chords of Memory can bring about peace and kinsman ship.

[Non-Sequitur]

And isn't that what he said here?

My countrymen, one and all, think calmly and well, upon this whole subject. Nothing valuable can be lost by taking time. If there be an object to hurry any of you, in hot haste, to a step which you would never take deliberately, that object will be frustrated by taking time; but no good object can be frustrated by it. Such of you as are now dissatisfied still have the old Constitution unimpaired, and, on the sensitive point, the laws of your own framing under it; while the new administration will have no immediate power, if it would, to change either. If it were admitted that you who are dissatisfied, hold the right side in the dispute, there still is no single good reason for precipitate action. Intelligence, patriotism, Christianity, and a firm reliance on Him, who has never yet forsaken this favored land, are still competent to adjust, in the best way, all our present difficulty.

In your hands, my dissatisfied fellow countrymen, and not in mine, is the momentous issue of civil war. The government will not assail you. You can have no conflict without being yourselves the aggressors. You have no oath registered in Heaven to destroy the government, while I shall have the most solemn one to "preserve, protect, and defend it."

I am loath to close. We are not enemies, but friends. We must not be enemies. Though passion may have strained, it must not break our bonds of affection. The mystic chords of memory, stretching from every battle-field, and patriot grave, to every living heart and hearth-stone, all over this broad land, will yet swell the chorus of the Union, when again touched, as surely they will be, by the better angels of our nature."

As for meeting with the commissioners, I would expect that supplying the fort with food fall under the "matters and subjects interesting to both nations" clause, which could only be brought up once recognition had been granted. In other words, once Lincoln had surrendered. You need to read the instructions and realize that they were not an offer to negotiate but an ultimatum demanding recognition before anything else could be done.