Cogito ergo sum "Je pense donc je suis" is a famous quote of René Descartes. It means "I think, therefore I am"
Je pense que je suis tombe d'amoureux. (if you're a boy.) Je pense que je suis tombee d'amoureuse. (if you're a girl.
The sentence 'Je pense donc je suis' means I think therefore I am. In the word-by-word translation, the personal pronoun 'je' means 'I'. The verb 'pense' means '[I] am thinking, do think, think'. The conjunction 'donc' means 'therefore'. The verb 'suis' means '[I] am'.
The English meaning of 'Je pense' is I think. In the word-by-word translation, the personal pronoun 'je' means 'I'. And the verb 'pense' means '[he/she/it] thinks'.
J'ai étudié toute la nuit, alors je suis très fatigué maintenant.
"well" can be translated to "bien" in French. So, you could say "bien, je pense cela" to say "well, I think this" in French.
je pense à toi - je suis en train de penser à toi (right now)
"I am very beautiful and I am here, but I think it is bad."
"Je suis plus intelligente alors" translates to "I am smarter then" in English.
I think you are amusing
I am smitten (as 'very much in love') with you: je suis fou de toi, je suis folle de toi
Cogito ergo sumor translate to the English «Je pense donc je suis » by Descarte
I believe i am in love with this... (but the French question has poor wording!)