Saalam alaikum wa rahamatu-llah
I'm sending you a couple of Hadeeth, hope that wll help you to understand inshaa'Allah.
Volume 9, Book 93, Number 471:
Narrated Abu Said Al-Khudri:
A man heard another man reciting (in the prayers): 'Say (O Muhammad): "He is Allah, the One." (112.1) And he recited it repeatedly. When it was morning, he went to the Prophet and informed him about that as if he considered that the recitation of that Sura by itself was not enough. Allah's Apostle said, "By Him in Whose Hand my life is, it is equal to one-third of the Quran."
Volume 9, Book 93, Number 472:
Narrated 'Aisha:
The Prophet sent (an army unit) under the command of a man who used to lead his companions in the prayers and would finish his recitation with (the Sura 112): 'Say (O Muhammad): "He is Allah, the One." ' (112.1) When they returned (from the battle), they mentioned that to the Prophet. He said (to them), "Ask him why he does so." They asked him and he said, "I do so because it mentions the qualities of the Beneficent and I love to recite it (in my prayer)." The Prophet; said (to them), "Tell him that Allah loves him"
I hope you have got that....so you can even finish one rakah with one ayah, if you dont know further or you love to recite that out of love for Allah azza wa jal.but usually we want to recite more, coz its human nature...but Allah loves the inclination to His worshipping, cncentration to Him.
I love sura Yasin to recite most.
Alhamdu li Allah, Shukran Allah....I've memorized the whole Sura....without the help of Allah I'd neve be able to do that..Inshaa'Allah I'm going further.
May Allah help you to memorize the whole Quran my brother.
JazakAllah khair
wassalam