Η φίλη μου γέλασε όταν είδε πόσα πράγματα είχα στο νεσεσέρ, αλλά τελικά δανείστηκε τη λοσιόν και τη βούρτσα μου.

In Modern Greek, the unstressed possessive words μου, σου, του, της, μας, σας, τους usually come after the noun.

So:

• η φίλη μου = my friend
• literally, it is closer to the friend of mine / the friend of me

This is the normal Greek pattern. English puts the possessive first; Greek usually puts it after the noun.

Also, μου is technically a genitive pronoun, but in sentences like this it works as a possessive.

Yes. Η φίλη μου can mean either:

• my female friend
• my girlfriend

Greek often leaves this to context. In this sentence, because the rest of the sentence is just about laughing and borrowing toiletries, the natural reading is my female friend.

These are all aorist forms, which in Modern Greek usually express a single completed event in the past.

• γέλασε = she laughed
• είδε = she saw
• δανείστηκε = she borrowed

That fits the story well: these are separate actions that happened and are viewed as complete.

A useful detail:

• είδε is the aorist of βλέπω (to see), and it is irregular.

Είχα is the normal past form of έχω in everyday Modern Greek.

So here:

• είχα στο νεσεσέρ = I had in the toiletry bag

It also fits the meaning well, because having things in the bag is a state/background situation, not a single sudden action.

So the sentence is basically saying:

• she laughed when she saw how many things I had in the bag

Πόσα πράγματα means how many things.

Why πόσα? Because it agrees with πράγματα, which is:

• neuter
• plural

So the matching form is πόσα.

Compare:

• πόσος for masculine singular
• πόση for feminine singular
• πόσο for neuter singular
• πόσοι / πόσες / πόσα for plurals

Here, πόσα πράγματα is an indirect question after είδε:

• είδε πόσα πράγματα είχα...
• she saw how many things I had...

Όταν means when.

In this sentence:

• γέλασε όταν είδε...
• she laughed when she saw...

It introduces a time clause. Since the sentence is talking about a real event in the past, Greek uses όταν with a past-tense verb:

• όταν είδε = when she saw

Στο is a contraction of:

• σε + το = στο

So:

• σε το νεσεσέρ becomes στο νεσεσέρ

Here σε means something like in / at / into, depending on context. In this sentence:

• στο νεσεσέρ = in the toiletry bag

Νεσεσέρ is a loanword, originally from French, and in Modern Greek it usually means a toiletry bag, wash bag, or sometimes a makeup bag.

It is generally treated as an indeclinable noun, which means the noun itself often stays the same:

• το νεσεσέρ
• στο νεσεσέρ
• του νεσεσέρ

The article changes, but the noun often does not.

This is a very common learner question.

In Greek:

• δανείζω = I lend
• δανείζομαι = I borrow

So:

• δανείστηκε = she borrowed

Even though the form looks like a middle/passive-type verb, its meaning here is active in English: borrow.

Compare:

• δάνεισε τη λοσιόν = she lent the lotion
• δανείστηκε τη λοσιόν = she borrowed the lotion

Greek very often repeats the definite article with coordinated nouns, especially when both are specific items.

So:

• τη λοσιόν και τη βούρτσα

is very natural Greek.

In English we often say the lotion and brush, with only one the, but Greek commonly repeats it:

• the lotion and the brush

This sounds clear and normal in Greek.

The feminine singular accusative article is often written as τη(ν) because the final -ν is sometimes kept and sometimes dropped.

In standard usage, the -ν is usually kept before:

• vowels
• κ, π, τ, ξ, ψ
• and combinations like μπ, ντ, γκ, τσ, τζ

Before many other consonants, it is often dropped.

So these are normal:

• τη λοσιόν
• τη βούρτσα

because λοσιόν begins with λ and βούρτσα begins with β.

Because one μου can apply to both nouns when they belong to the same person.

So:

• τη λοσιόν και τη βούρτσα μου

means:

• my lotion and brush
• or more literally, the lotion and the brush of mine

Greek often puts the possessive only once at the end of the whole noun phrase if it clearly belongs to both items.

You could also say:

• τη λοσιόν μου και τη βούρτσα μου

but that sounds more emphatic or more explicit.

Τελικά means something like:

• in the end
• eventually
• after all

It adds a nice contrast here:

• she laughed at how many things I had,
• but in the end she borrowed some of them anyway

So τελικά helps show the irony or twist in the sentence.

They are the direct objects of δανείστηκε.

She borrowed what?

• τη λοσιόν
• τη βούρτσα

That is why Greek uses the accusative forms here. For feminine singular nouns, you mainly notice this in the article:

• nominative: η βούρτσα
• accusative: τη(ν) βούρτσα

The same idea applies to η λοσιόν → τη λοσιόν.