In plain words
A yajña performed according to rule by those who seek no fruit, with manas firmly resolved that it simply ought to be offered, is sāttvika.
Word for word
The yajña which, seen in the injunction, is offered by those not craving fruit, having settled the manas [thus]: '[it] is only to be offered', that [is] sāttvika.
अफलाकाङ्क्षिभिर्यज्ञो विधिदृष्टो य इज्यतेयष्टव्यमेवेति मनः समाधाय स सात्त्विकः
Other commentaries
The commentators
▸Bhagavadgītābhāṣyam
अथ इदानीं यज्ञः त्रिविधः उच्यते —
अफलाकाङ्क्षिभिः अफलार्थिभिः यज्ञः विधिदृष्टः शास्त्रचोदनादृष्टो यः यज्ञः इज्यते निर्वर्त्यते, यष्टव्यमेवेति यज्ञस्वरूपनिर्वर्तनमेव कार्यम् इति मनः समाधाय, न अनेन पुरुषार्थो मम कर्तव्यः इत्येवं निश्चित्य, सः सात्त्विकः यज्ञः उच्यते ॥ ११ ॥
In plain words
Now, right here, yajña is taken up — and it is said to be of three kinds:
By people who want no fruit from it — who are not after a result at all — the sacrifice that scripture itself lays down, that is, the one made visible by scripture's own prompting: when that sacrifice is offered, when it is carried through, with the mind settled in this — the offering is simply to be made; carrying out the rite's own form is the whole of the duty — and with this decided, no aim of mine is to be accomplished by this: that sacrifice is called sāttvika. || 11 ||
Close to the Sanskrit
Now, at this point, sacrifice is said to be threefold —
By those not craving fruit — by those not seeking fruit — the sacrifice seen by injunction, that is, seen through the prompting of scripture, which sacrifice is offered, is brought to completion, having composed the mind thus, 'it is simply to be offered,' 'the mere carrying out of the sacrifice's own form is the duty,' having determined thus, 'no personal aim of mine is to be accomplished by this' — that sacrifice is called sāttvika. || 11 ||