After mentioning the believers and describing them in the beginning of the surah, Allah went forth mentioning the disbelievers and describing them. And then came to the description of those in the middle: Those who say they believe while they actually only act like believers!
Imam ibn Kathir introduced these verses in his tafsir by saying:
We mentioned that four Ayat in the beginning of Surat Al-Baqarah described the believers. The two last Ayat (2:6-7) describe the disbelievers. Afterwards, Allah begins to describe the hypocrites who show belief and hide disbelief. Since the matter of the hypocrites is vague and many people do not realize their true reality, Allah mentioned their description in detail. Each of the characteristics that Allah used to described them with is a type of hypocrisy itself. Allah revealed Surat Bara'ah (chapter 9) and Surat Al-Munafiqun (chapter 63) about the hypocrites. He also mentioned the hypocrites in Surat An-Nur (24) and other Surahs, so that their description would be known and their ways and errors could be avoided. Allah said,
(8. And of mankind, there are some who say: "We believe in Allah and the Last Day'' while in fact they do not believe). (9. They try to deceive Allah and those who believe, while they only deceive themselves, and perceive (it) not!) (Source: qtafsir)
Then he moved on describing the hypocrites:
Nifaq means to show conformity - or agreement - and to conceal evil. Nifaq has several types: Nifaq in the creed that causes its people to reside in Hell for eternity, and Nifaq in deed, which is one of the major sins, as we will explain soon, Allah willing. Ibn Jurayj said of the hypocrite that, "His actual deeds are different from what he publicizes, what he conceals is different from what he utters, his entrance and presence are not the same as his exit and absence.'' (Source qtafsir)
I strongly recommend you to check the following pages on qtafsir for further information and details on the verses. Even if I must warn you that they may deviuate a bit by quoting the cirucmstances and history of the revelation of these verses too.
The last verse of your quote (2:10):
In their hearts is disease, so Allah has increased their disease; and for them is a painful punishment because they [habitually] used to lie.
actually has counter part or reference in the Qur'an:
And whenever a surah is revealed, there are among the hypocrites those who say, "Which of you has this increased faith?" As for those who believed, it has increased them in faith, while they are rejoicing. (124)
But as for those in whose hearts is disease, it has [only] increased them in evil [in addition] to their evil. And they will have died while they are disbelievers. (9:124-125)
Most scholars say Imaan: Is saying and doing. This means believing by heart and expression and applying. As kufr in Arabic also means rejection while imaan means approval.
In your current state you need to learn about Islam and it is ok to have questions and doubts and its highly recommended to clear these doubts as "Allah loves/prefers to be worshiped by knowledge" as many scholars say, this means you must know and try to seek proofs to create a strong knowledge base against possibly upcoming doubts. As as long as you just blindly follow it is certain that your doubts may grow, while when you know why you do it, you get certainty. Therefore Allah points at this in the Qur'an saying:
And most of them follow not except assumption. Indeed, assumption avails not against the truth at all. Indeed, Allah is Knowing of what they do. (10:36)
And they have thereof no knowledge. They follow not except assumption, and indeed, assumption avails not against the truth at all. (53:28)
So if you have any doubt feel free to clear it by formulating it as questions and ask Muslims of your trust, scholars and ask for evidences as they might help you understand and accept and strengthen your imaan.